diff --git a/VERSION b/VERSION
index 201a22c..c5523bd 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.16.2
+0.17.0
diff --git a/backend/app/auth.py b/backend/app/auth.py
index 1ac8bee..f71b55a 100644
--- a/backend/app/auth.py
+++ b/backend/app/auth.py
@@ -1,6 +1,4 @@
-import hashlib
 import logging
-import re
 import secrets
 from datetime import datetime, timedelta, timezone
 
@@ -8,7 +6,7 @@ import httpx
 from authlib.integrations.starlette_client import OAuth, OAuthError
 from fastapi import APIRouter, BackgroundTasks, Depends, HTTPException, Request
 from fastapi.responses import JSONResponse, RedirectResponse
-from sqlalchemy import delete, select
+from sqlalchemy import delete, func, select
 from sqlalchemy.orm import Session
 
 from app import email as email_mod
@@ -17,7 +15,8 @@ from app.config import settings
 from app.db import get_db
 from app.models import AuthToken, DemoWhitelist, Invite, OAuthToken, User
 from app.ratelimit import RateLimiter
-from app.security import decrypt, encrypt, hash_password, verify_password
+from app.security import decrypt, encrypt, hash_password, hash_token, verify_password
+from app.utils import valid_email
 
 # Email+password auth tuning.
 PASSWORD_MIN_LEN = 10
@@ -43,8 +42,6 @@ def _notify_suspended(background: BackgroundTasks, email: str) -> None:
     if _suspend_email_limiter.allow(email):
         background.add_task(email_mod.send_account_suspended, email, operator_contact())
 
-_EMAIL_RE = re.compile(r"^[^@\s]+@[^@\s]+\.[^@\s]+$")
-
 # The single shared demo account's stable identity. The row is created lazily on first
 # demo login (see get_or_create_demo_user); these are just its sentinel keys.
 DEMO_GOOGLE_SUB = "__demo__"
@@ -184,7 +181,7 @@ def upsert_pending_invite(db: Session, email: str) -> Invite | None:
     """Idempotently record an access request. Returns the Invite if a *new* pending row
     was created (so the caller can notify admins), else None for already-known emails."""
     email = (email or "").lower()
-    if not _EMAIL_RE.match(email):
+    if not valid_email(email):
         return None
     inv = db.execute(select(Invite).where(Invite.email == email)).scalar_one_or_none()
     if inv is not None:
@@ -443,7 +440,7 @@ async def request_access(
     """Public: ask for access. Idempotent — repeat requests for the same email don't
     duplicate or re-spam admins (upsert returns None for an already-pending row)."""
     email = (payload.get("email") or "").strip().lower()
-    if not _EMAIL_RE.match(email):
+    if not valid_email(email):
         raise HTTPException(status_code=400, detail="Enter a valid email address.")
     if is_allowed(db, email):
         return {"status": "approved"}  # already allowed — just sign in
@@ -465,7 +462,7 @@ def demo_login(payload: dict, request: Request, db: Session = Depends(get_db)) -
     if not _demo_limiter.allow(_client_ip(request)):
         return {"authenticated": False}
     email = (payload.get("email") or "").strip().lower()
-    if _EMAIL_RE.match(email) and is_demo_allowed(db, email):
+    if valid_email(email) and is_demo_allowed(db, email):
         demo = get_or_create_demo_user(db)
         request.session["user_id"] = demo.id
         log.info("Demo login (key=%s, demo_id=%s)", email, demo.id)
@@ -487,10 +484,6 @@ def _app_base() -> str:
     return settings.app_base
 
 
-def _hash_token(raw: str) -> str:
-    return hashlib.sha256(raw.encode()).hexdigest()
-
-
 def _issue_token(db: Session, user: User, kind: str, ttl: timedelta) -> str:
     """Create a single-use token of `kind`; only its hash is stored. Returns the raw token
     (goes only into the emailed link)."""
@@ -499,7 +492,7 @@ def _issue_token(db: Session, user: User, kind: str, ttl: timedelta) -> str:
         AuthToken(
             user_id=user.id,
             kind=kind,
-            token_hash=_hash_token(raw),
+            token_hash=hash_token(raw),
             expires_at=datetime.now(timezone.utc) + ttl,
         )
     )
@@ -513,7 +506,7 @@ def _consume_token(db: Session, raw: str | None, kind: str) -> User | None:
         return None
     row = db.execute(
         select(AuthToken).where(
-            AuthToken.token_hash == _hash_token(raw), AuthToken.kind == kind
+            AuthToken.token_hash == hash_token(raw), AuthToken.kind == kind
         )
     ).scalar_one_or_none()
     if row is None or row.used_at is not None or row.expires_at < datetime.now(timezone.utc):
@@ -537,7 +530,7 @@ def register(
     email = (payload.get("email") or "").strip().lower()
     password = payload.get("password") or ""
     # Input validation is safe to reveal (independent of whether the email exists).
-    if not _EMAIL_RE.match(email):
+    if not valid_email(email):
         raise HTTPException(status_code=400, detail="Enter a valid email address.")
     if len(password) < PASSWORD_MIN_LEN:
         raise HTTPException(
@@ -633,7 +626,7 @@ def password_reset_request(
     if not _reset_limiter.allow(_client_ip(request)):
         return {"status": "ok"}
     email = (payload.get("email") or "").strip().lower()
-    if _EMAIL_RE.match(email):
+    if valid_email(email):
         user = db.execute(select(User).where(User.email == email)).scalar_one_or_none()
         if user is not None and user.password_hash and not user.is_demo:
             raw = _issue_token(db, user, "reset", RESET_TTL)
@@ -694,6 +687,23 @@ def require_human(user: User = Depends(current_user)) -> User:
     return user
 
 
+def admin_user(user: User = Depends(current_user)) -> User:
+    """Dependency: require the signed-in user to be an admin. Single source of truth for the
+    admin gate — every admin route/action depends on this rather than re-checking the role."""
+    if user.role != "admin":
+        raise HTTPException(status_code=403, detail="Admin only")
+    return user
+
+
+def count_admins(db: Session, *, active_only: bool = False) -> int:
+    """How many admins exist (optionally only un-suspended ones). Used by the 'can't remove /
+    suspend / delete the last admin' guards so they don't each re-spell the count query."""
+    q = select(func.count()).select_from(User).where(User.role == "admin")
+    if active_only:
+        q = q.where(User.is_suspended.is_(False))
+    return db.scalar(q) or 0
+
+
 @router.get("/link")
 async def link_google(
     request: Request,
diff --git a/backend/app/models.py b/backend/app/models.py
index 86226b3..4ebf14d 100644
--- a/backend/app/models.py
+++ b/backend/app/models.py
@@ -19,7 +19,24 @@ from sqlalchemy.orm import Mapped, mapped_column, relationship
 from app.db import Base
 
 
-class User(Base):
+class TimestampMixin:
+    """Adds a server-defaulted `created_at`. Models that index created_at or order it
+    differently (QuotaEvent, Notification, Message) keep their own column on purpose."""
+
+    created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), server_default=func.now()
+    )
+
+
+class UpdatedAtMixin:
+    """Adds an `updated_at` that server-defaults on insert and bumps on every UPDATE."""
+
+    updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), server_default=func.now(), onupdate=func.now()
+    )
+
+
+class User(Base, TimestampMixin):
     __tablename__ = "users"
 
     id: Mapped[int] = mapped_column(primary_key=True)
@@ -57,9 +74,6 @@ class User(Base):
     )
     # Free-form UI preferences (theme, color scheme, font scale, default filters…).
     preferences: Mapped[dict | None] = mapped_column(JSON)
-    created_at: Mapped[datetime] = mapped_column(
-        DateTime(timezone=True), server_default=func.now()
-    )
 
     token: Mapped["OAuthToken | None"] = relationship(
         back_populates="user", uselist=False, cascade="all, delete-orphan"
@@ -69,7 +83,7 @@ class User(Base):
     )
 
 
-class OAuthToken(Base):
+class OAuthToken(Base, UpdatedAtMixin):
     __tablename__ = "oauth_tokens"
 
     id: Mapped[int] = mapped_column(primary_key=True)
@@ -81,14 +95,11 @@ class OAuthToken(Base):
     access_token: Mapped[str | None] = mapped_column(String)
     expiry: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))
     scopes: Mapped[str | None] = mapped_column(String)
-    updated_at: Mapped[datetime] = mapped_column(
-        DateTime(timezone=True), server_default=func.now(), onupdate=func.now()
-    )
 
     user: Mapped["User"] = relationship(back_populates="token")
 
 
-class AuthToken(Base):
+class AuthToken(Base, TimestampMixin):
     """Single-use, expiring token for email verification or password reset. Only the SHA-256
     HASH of the token is stored, so a DB leak can't be used to verify/reset; the raw token
     lives only in the emailed link. Consumed (used_at set) on first valid use."""
@@ -103,9 +114,6 @@ class AuthToken(Base):
     token_hash: Mapped[str] = mapped_column(String(64), unique=True, index=True)
     expires_at: Mapped[datetime] = mapped_column(DateTime(timezone=True))
     used_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))
-    created_at: Mapped[datetime] = mapped_column(
-        DateTime(timezone=True), server_default=func.now()
-    )
 
 
 class Invite(Base):
@@ -128,7 +136,7 @@ class Invite(Base):
     decided_by: Mapped[str | None] = mapped_column(String(320))  # admin email
 
 
-class DemoWhitelist(Base):
+class DemoWhitelist(Base, TimestampMixin):
     """Emails that may enter the shared demo account from the login page (no Google OAuth).
     A hidden, admin-curated list of "keys to the same door" — every entry logs into the one
     shared demo user. Distinct from Invite (which gates real Google sign-in)."""
@@ -139,12 +147,9 @@ class DemoWhitelist(Base):
     email: Mapped[str] = mapped_column(String(320), unique=True, index=True)
     note: Mapped[str | None] = mapped_column(Text)
     added_by: Mapped[str | None] = mapped_column(String(320))  # admin email
-    created_at: Mapped[datetime] = mapped_column(
-        DateTime(timezone=True), server_default=func.now()
-    )
 
 
-class Channel(Base):
+class Channel(Base, TimestampMixin):
     """A YouTube channel. Shared across all users (one channel's videos are the same
     for everyone), so its expensive metadata is fetched and stored only once."""
 
@@ -170,15 +175,12 @@ class Channel(Base):
     backfill_done: Mapped[bool] = mapped_column(
         Boolean, default=False, server_default="false"
     )
-    created_at: Mapped[datetime] = mapped_column(
-        DateTime(timezone=True), server_default=func.now()
-    )
 
     videos: Mapped[list["Video"]] = relationship(back_populates="channel")
     subscriptions: Mapped[list["Subscription"]] = relationship(back_populates="channel")
 
 
-class Subscription(Base):
+class Subscription(Base, TimestampMixin):
     """Per-user link to a channel, with the user's own priority/visibility overrides."""
 
     __tablename__ = "subscriptions"
@@ -202,15 +204,12 @@ class Subscription(Base):
         Boolean, default=False, server_default="false"
     )
     subscribed_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))
-    created_at: Mapped[datetime] = mapped_column(
-        DateTime(timezone=True), server_default=func.now()
-    )
 
     user: Mapped["User"] = relationship(back_populates="subscriptions")
     channel: Mapped["Channel"] = relationship(back_populates="subscriptions")
 
 
-class Video(Base):
+class Video(Base, TimestampMixin):
     """A YouTube video. Shared across users; per-user state lives elsewhere."""
 
     __tablename__ = "videos"
@@ -260,14 +259,11 @@ class Video(Base):
         DateTime(timezone=True), index=True
     )
     unavailable_reason: Mapped[str | None] = mapped_column(String(24))
-    created_at: Mapped[datetime] = mapped_column(
-        DateTime(timezone=True), server_default=func.now()
-    )
 
     channel: Mapped["Channel"] = relationship(back_populates="videos")
 
 
-class Tag(Base):
+class Tag(Base, TimestampMixin):
     """A label. System tags (user_id NULL) are computed automatically and shared by all
     users; user tags (user_id set) are personal. category groups them in the UI."""
 
@@ -283,9 +279,6 @@ class Tag(Base):
     category: Mapped[str] = mapped_column(
         String(16), default="other", server_default="other"
     )
-    created_at: Mapped[datetime] = mapped_column(
-        DateTime(timezone=True), server_default=func.now()
-    )
 
 
 class ChannelTag(Base):
@@ -312,7 +305,7 @@ class ChannelTag(Base):
     confidence: Mapped[float | None] = mapped_column(Float)
 
 
-class VideoState(Base):
+class VideoState(Base, UpdatedAtMixin):
     """Per-user watch state for a video. Rows exist only for non-default states; the
     absence of a row means 'new/unseen'."""
 
@@ -326,7 +319,7 @@ class VideoState(Base):
     video_id: Mapped[str] = mapped_column(
         ForeignKey("videos.id", ondelete="CASCADE"), index=True
     )
-    # new | watched | saved | hidden
+    # new | watched | hidden  ("saved" is now Watch-later playlist membership, not a status)
     status: Mapped[str] = mapped_column(String(12), default="new", server_default="new")
     watched_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))
     # Resume position (seconds into the video) for the in-app player. Orthogonal to
@@ -337,9 +330,6 @@ class VideoState(Base):
         Integer, default=0, server_default="0", nullable=False
     )
     progress_updated_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))
-    updated_at: Mapped[datetime] = mapped_column(
-        DateTime(timezone=True), server_default=func.now(), onupdate=func.now()
-    )
 
 
 class ApiQuotaUsage(Base):
@@ -422,7 +412,7 @@ class SystemConfig(Base):
     )
 
 
-class Playlist(Base):
+class Playlist(Base, TimestampMixin, UpdatedAtMixin):
     """A per-user named, ordered collection of videos from the shared catalog.
 
     `kind`: 'user' (normal) or 'watch_later' (built-in, undeletable, one per user).
@@ -450,12 +440,6 @@ class Playlist(Base):
     # baseline `dirty` is derived against. NULL = no baseline yet (treated as dirty).
     synced_fingerprint: Mapped[str | None] = mapped_column(String)
     position: Mapped[int] = mapped_column(Integer, default=0, server_default="0")
-    created_at: Mapped[datetime] = mapped_column(
-        DateTime(timezone=True), server_default=func.now()
-    )
-    updated_at: Mapped[datetime] = mapped_column(
-        DateTime(timezone=True), server_default=func.now(), onupdate=func.now()
-    )
 
     items: Mapped[list["PlaylistItem"]] = relationship(
         back_populates="playlist",
@@ -560,7 +544,7 @@ class Message(Base):
     )
 
 
-class MessageKey(Base):
+class MessageKey(Base, TimestampMixin):
     """A user's end-to-end-encryption key material for direct messaging (phase 2).
 
     One row per user. `public_key` (base64 SPKI, ECDH P-256) is shared with others so they can
@@ -581,6 +565,3 @@ class MessageKey(Base):
     salt: Mapped[str] = mapped_column(String(64))
     wrap_iv: Mapped[str] = mapped_column(String(32))
     key_check: Mapped[str] = mapped_column(Text)
-    created_at: Mapped[datetime] = mapped_column(
-        DateTime(timezone=True), server_default=func.now()
-    )
diff --git a/backend/app/quota.py b/backend/app/quota.py
index be699a1..1a45011 100644
--- a/backend/app/quota.py
+++ b/backend/app/quota.py
@@ -66,6 +66,26 @@ def attribute(actor_id: int | None, action: str):
         _action.reset(t2)
 
 
+class Measure:
+    """Result handle from `measured()` — read .used / .remaining after the block exits."""
+
+    used = 0
+    remaining = 0
+
+
+@contextlib.contextmanager
+def measured(db: Session, actor_id: int | None, action: str):
+    """Like `attribute()`, but also reports how much quota the block spent. Yields a `Measure`
+    whose `.used` (units charged inside the block) and `.remaining` (today's remaining after)
+    are populated on exit — so manual sync routes don't each re-spell the before/after diff."""
+    m = Measure()
+    before = units_used_today(db)
+    with attribute(actor_id, action):
+        yield m
+    m.used = units_used_today(db) - before
+    m.remaining = remaining_today(db)
+
+
 def pacific_today():
     return datetime.now(_PACIFIC).date()
 
diff --git a/backend/app/routes/admin.py b/backend/app/routes/admin.py
index 1f7d3d8..722ac3c 100644
--- a/backend/app/routes/admin.py
+++ b/backend/app/routes/admin.py
@@ -1,6 +1,5 @@
 """Admin-only onboarding: review access requests (Invites), approve/deny, manual add.
 Also the demo-account admin surface: the demo email whitelist + a manual state reset."""
-import re
 from datetime import datetime, timezone
 
 from fastapi import APIRouter, BackgroundTasks, Depends, HTTPException
@@ -8,7 +7,13 @@ from sqlalchemy import delete, func, select
 from sqlalchemy.orm import Session
 
 from app import email as email_mod
-from app.auth import current_user, get_or_create_demo_user, operator_contact, purge_user
+from app.auth import (
+    admin_user,
+    count_admins,
+    get_or_create_demo_user,
+    operator_contact,
+    purge_user,
+)
 from app.db import get_db
 from app.models import (
     DemoWhitelist,
@@ -20,17 +25,10 @@ from app.models import (
     Video,
     VideoState,
 )
+from app.utils import valid_email
 
 router = APIRouter(prefix="/api/admin", tags=["admin"])
 
-_EMAIL_RE = re.compile(r"^[^@\s]+@[^@\s]+\.[^@\s]+$")
-
-
-def admin_user(user: User = Depends(current_user)) -> User:
-    if user.role != "admin":
-        raise HTTPException(status_code=403, detail="Admin only")
-    return user
-
 
 def _serialize(inv: Invite) -> dict:
     return {
@@ -110,7 +108,7 @@ def add_invite(
 ) -> dict:
     """Manually whitelist an email (approved straight away). Convenience for the admin."""
     email = (payload.get("email") or "").strip().lower()
-    if "@" not in email:
+    if not valid_email(email):
         raise HTTPException(status_code=400, detail="Enter a valid email address.")
     inv = db.execute(select(Invite).where(Invite.email == email)).scalar_one_or_none()
     if inv is None:
@@ -168,10 +166,8 @@ def set_user_role(
         raise HTTPException(status_code=400, detail="The demo account's role can't be changed.")
     if target.id == admin.id:
         raise HTTPException(status_code=400, detail="You can't change your own role.")
-    if target.role == "admin" and role == "user":
-        admin_count = db.scalar(select(func.count()).select_from(User).where(User.role == "admin"))
-        if (admin_count or 0) <= 1:
-            raise HTTPException(status_code=400, detail="Can't remove the last admin.")
+    if target.role == "admin" and role == "user" and count_admins(db) <= 1:
+        raise HTTPException(status_code=400, detail="Can't remove the last admin.")
     changed = target.role != role
     target.role = role
     db.commit()
@@ -201,14 +197,13 @@ def set_user_suspended(
         raise HTTPException(status_code=400, detail="The demo account can't be suspended.")
     if target.id == admin.id:
         raise HTTPException(status_code=400, detail="You can't suspend your own account.")
-    if suspended and target.role == "admin" and not target.is_suspended:
-        active_admins = db.scalar(
-            select(func.count())
-            .select_from(User)
-            .where(User.role == "admin", User.is_suspended.is_(False))
-        )
-        if (active_admins or 0) <= 1:
-            raise HTTPException(status_code=400, detail="Can't suspend the last active admin.")
+    if (
+        suspended
+        and target.role == "admin"
+        and not target.is_suspended
+        and count_admins(db, active_only=True) <= 1
+    ):
+        raise HTTPException(status_code=400, detail="Can't suspend the last active admin.")
     was_suspended = target.is_suspended
     target.is_suspended = suspended
     db.commit()
@@ -238,12 +233,8 @@ def admin_delete_user(
         raise HTTPException(
             status_code=400, detail="Delete your own account from Settings → Account."
         )
-    if target.role == "admin":
-        admin_count = db.scalar(
-            select(func.count()).select_from(User).where(User.role == "admin")
-        )
-        if (admin_count or 0) <= 1:
-            raise HTTPException(status_code=400, detail="Can't delete the last admin.")
+    if target.role == "admin" and count_admins(db) <= 1:
+        raise HTTPException(status_code=400, detail="Can't delete the last admin.")
     purge_user(db, target, background)
     return {"deleted": user_id}
 
@@ -281,7 +272,7 @@ def add_demo_whitelist(
     """Add an email that may enter the shared demo account from the login page (no Google
     sign-in). Idempotent — re-adding an existing email just returns it."""
     email = (payload.get("email") or "").strip().lower()
-    if not _EMAIL_RE.match(email):
+    if not valid_email(email):
         raise HTTPException(status_code=400, detail="Enter a valid email address.")
     row = db.execute(
         select(DemoWhitelist).where(DemoWhitelist.email == email)
diff --git a/backend/app/routes/feed.py b/backend/app/routes/feed.py
index e2f331a..7e43f08 100644
--- a/backend/app/routes/feed.py
+++ b/backend/app/routes/feed.py
@@ -62,6 +62,29 @@ def _saved_expr(user: User):
     )
 
 
+def feed_columns(user: User, state) -> list:
+    """The shared feed-row projection (joined Channel fields + per-user watch state +
+    `saved`), consumed by both the feed query and the playlist-detail query so a new column
+    is added in exactly one place. `state` is the caller's aliased VideoState (outer-joined)."""
+    return [
+        Video.id,
+        Video.title,
+        Video.channel_id,
+        Channel.title.label("channel_title"),
+        Channel.thumbnail_url.label("channel_thumbnail"),
+        Channel.handle.label("channel_handle"),
+        Video.published_at,
+        Video.thumbnail_url,
+        Video.duration_seconds,
+        Video.view_count,
+        Video.is_short,
+        Video.live_status,
+        func.coalesce(state.status, "new").label("status"),
+        func.coalesce(state.position_seconds, 0).label("position_seconds"),
+        _saved_expr(user),
+    ]
+
+
 def _serialize(row) -> dict:
     return {
         "id": row.id,
@@ -115,23 +138,9 @@ def _filtered_query(
     status_expr = func.coalesce(state.status, "new")
     position_expr = func.coalesce(state.position_seconds, 0)
 
-    query = select(
-        Video.id,
-        Video.title,
-        Video.channel_id,
-        Channel.title.label("channel_title"),
-        Channel.thumbnail_url.label("channel_thumbnail"),
-        Channel.handle.label("channel_handle"),
-        Video.published_at,
-        Video.thumbnail_url,
-        Video.duration_seconds,
-        Video.view_count,
-        Video.is_short,
-        Video.live_status,
-        status_expr.label("status"),
-        position_expr.label("position_seconds"),
-        _saved_expr(user),
-    ).join(Channel, Channel.id == Video.channel_id)
+    query = select(*feed_columns(user, state)).join(
+        Channel, Channel.id == Video.channel_id
+    )
 
     if scope == "all":
         # Whole shared catalog; subscription is optional (only for priority sort).
diff --git a/backend/app/routes/me.py b/backend/app/routes/me.py
index 26498b4..dca46a9 100644
--- a/backend/app/routes/me.py
+++ b/backend/app/routes/me.py
@@ -3,6 +3,7 @@ from sqlalchemy import func, select
 from sqlalchemy.orm import Session
 
 from app.auth import (
+    count_admins,
     current_user,
     google_enabled,
     has_read_scope,
@@ -111,13 +112,11 @@ def delete_my_account(
     (that would lock everyone out of the admin surfaces)."""
     if user.is_demo:
         raise HTTPException(status_code=403, detail="The shared demo account can't be deleted.")
-    if user.role == "admin":
-        admins = db.scalar(select(func.count()).select_from(User).where(User.role == "admin")) or 0
-        if admins <= 1:
-            raise HTTPException(
-                status_code=400,
-                detail="You're the only admin — promote another admin before deleting your account.",
-            )
+    if user.role == "admin" and count_admins(db) <= 1:
+        raise HTTPException(
+            status_code=400,
+            detail="You're the only admin — promote another admin before deleting your account.",
+        )
     user_id = user.id
     # Full erasure (cascades) + access-request cleanup + Google-grant revocation; shared with the
     # admin delete path. Capture the id first — `user` is detached once purge_user deletes the row.
diff --git a/backend/app/routes/messages.py b/backend/app/routes/messages.py
index 59998a4..9718e1d 100644
--- a/backend/app/routes/messages.py
+++ b/backend/app/routes/messages.py
@@ -103,6 +103,7 @@ def _serialize_msg(m: Message) -> dict:
 
 
 def _messageable() -> list:
+    """SQL clauses for "a real, active, non-suspended human" — for directory/recipient queries."""
     return [
         User.is_demo.is_(False),
         User.is_active.is_(True),
@@ -110,6 +111,11 @@ def _messageable() -> list:
     ]
 
 
+def is_messageable_user(u: User | None) -> bool:
+    """Python mirror of `_messageable()` for an already-loaded row (WS auth, send recipient)."""
+    return bool(u and not u.is_demo and u.is_active and not u.is_suspended)
+
+
 def ensure_welcome(db: Session, user: User) -> None:
     """Create the one-time system welcome message for a (human) user the first time it's needed.
     Idempotent: guarded on whether any system message already exists for them."""
@@ -315,7 +321,7 @@ def send_message(
     if payload.recipient_id == user.id:
         raise HTTPException(status_code=400, detail="You can't message yourself.")
     recipient = db.get(User, payload.recipient_id)
-    if recipient is None or recipient.is_demo or not recipient.is_active or recipient.is_suspended:
+    if not is_messageable_user(recipient):
         raise HTTPException(status_code=404, detail="Recipient not available.")
     if db.get(MessageKey, recipient.id) is None:
         raise HTTPException(status_code=404, detail="That member hasn't set up messaging yet.")
@@ -363,8 +369,7 @@ async def messages_ws(ws: WebSocket) -> None:
         return
     db = SessionLocal()
     try:
-        u = db.get(User, uid)
-        ok = bool(u and not u.is_demo and not u.is_suspended and u.is_active)
+        ok = is_messageable_user(db.get(User, uid))
     finally:
         db.close()
     if not ok:
diff --git a/backend/app/routes/playlists.py b/backend/app/routes/playlists.py
index 89228cb..a3ebf8a 100644
--- a/backend/app/routes/playlists.py
+++ b/backend/app/routes/playlists.py
@@ -9,7 +9,7 @@ from app import quota
 from app.auth import current_user, has_read_scope, has_write_scope
 from app.db import get_db
 from app.models import Channel, Playlist, PlaylistItem, User, Video, VideoState
-from app.routes.feed import _saved_expr, _serialize
+from app.routes.feed import _serialize, feed_columns
 from app.sync.playlists import (
     plan_push,
     push_playlist,
@@ -29,6 +29,51 @@ def _own_playlist(db: Session, user: User, playlist_id: int) -> Playlist:
     return pl
 
 
+def _next_playlist_position(db: Session, user_id: int) -> int:
+    """Append position for a new playlist in this user's rail."""
+    return (
+        db.scalar(
+            select(func.coalesce(func.max(Playlist.position), -1)).where(
+                Playlist.user_id == user_id
+            )
+        )
+        + 1
+    )
+
+
+def _next_item_position(db: Session, playlist_id: int) -> int:
+    """Append position for a new item at the end of a playlist."""
+    return (
+        db.scalar(
+            select(func.coalesce(func.max(PlaylistItem.position), -1)).where(
+                PlaylistItem.playlist_id == playlist_id
+            )
+        )
+        + 1
+    )
+
+
+def _add_item(db: Session, pl: Playlist, video_id: str, *, mark_dirty: bool) -> bool:
+    """Append a video to a playlist if not already present (idempotent). Returns whether it
+    was added. `mark_dirty` recomputes the YouTube-sync dirty flag (skip for Watch later)."""
+    exists = db.scalar(
+        select(PlaylistItem).where(
+            PlaylistItem.playlist_id == pl.id, PlaylistItem.video_id == video_id
+        )
+    )
+    if exists is not None:
+        return False
+    db.add(
+        PlaylistItem(
+            playlist_id=pl.id, video_id=video_id, position=_next_item_position(db, pl.id)
+        )
+    )
+    if mark_dirty:
+        recompute_dirty(db, pl)
+    db.commit()
+    return True
+
+
 def _summary(
     db: Session,
     pl: Playlist,
@@ -142,15 +187,7 @@ def create_playlist(
     name = (payload.get("name") or "").strip()
     if not name:
         raise HTTPException(status_code=400, detail="name is required")
-    next_pos = (
-        db.scalar(
-            select(func.coalesce(func.max(Playlist.position), -1)).where(
-                Playlist.user_id == user.id
-            )
-        )
-        + 1
-    )
-    pl = Playlist(user_id=user.id, name=name, position=next_pos)
+    pl = Playlist(user_id=user.id, name=name, position=_next_playlist_position(db, user.id))
     db.add(pl)
     db.commit()
     return _summary(db, pl, 0)
@@ -164,16 +201,11 @@ def _watch_later(db: Session, user: User) -> Playlist:
         )
     )
     if pl is None:
-        next_pos = (
-            db.scalar(
-                select(func.coalesce(func.max(Playlist.position), -1)).where(
-                    Playlist.user_id == user.id
-                )
-            )
-            + 1
-        )
         pl = Playlist(
-            user_id=user.id, name="Watch later", kind="watch_later", position=next_pos
+            user_id=user.id,
+            name="Watch later",
+            kind="watch_later",
+            position=_next_playlist_position(db, user.id),
         )
         db.add(pl)
         db.commit()
@@ -191,22 +223,7 @@ def add_watch_later(
     if not video_id or db.get(Video, video_id) is None:
         raise HTTPException(status_code=404, detail="Unknown video")
     pl = _watch_later(db, user)
-    exists = db.scalar(
-        select(PlaylistItem).where(
-            PlaylistItem.playlist_id == pl.id, PlaylistItem.video_id == video_id
-        )
-    )
-    if exists is None:
-        next_pos = (
-            db.scalar(
-                select(func.coalesce(func.max(PlaylistItem.position), -1)).where(
-                    PlaylistItem.playlist_id == pl.id
-                )
-            )
-            + 1
-        )
-        db.add(PlaylistItem(playlist_id=pl.id, video_id=video_id, position=next_pos))
-        db.commit()
+    _add_item(db, pl, video_id, mark_dirty=False)
     return {"saved": True, "playlist_id": pl.id}
 
 
@@ -344,23 +361,7 @@ def get_playlist(
     pl = _own_playlist(db, user, playlist_id)
     state = aliased(VideoState)
     rows = db.execute(
-        select(
-            Video.id,
-            Video.title,
-            Video.channel_id,
-            Channel.title.label("channel_title"),
-            Channel.thumbnail_url.label("channel_thumbnail"),
-            Channel.handle.label("channel_handle"),
-            Video.published_at,
-            Video.thumbnail_url,
-            Video.duration_seconds,
-            Video.view_count,
-            Video.is_short,
-            Video.live_status,
-            func.coalesce(state.status, "new").label("status"),
-            func.coalesce(state.position_seconds, 0).label("position_seconds"),
-            _saved_expr(user),
-        )
+        select(*feed_columns(user, state))
         .join(PlaylistItem, PlaylistItem.video_id == Video.id)
         .join(Channel, Channel.id == Video.channel_id)
         .outerjoin(state, and_(state.video_id == Video.id, state.user_id == user.id))
@@ -439,25 +440,7 @@ def add_item(
     video_id = payload.get("video_id")
     if not video_id or db.get(Video, video_id) is None:
         raise HTTPException(status_code=404, detail="Unknown video")
-    exists = db.scalar(
-        select(PlaylistItem).where(
-            PlaylistItem.playlist_id == pl.id, PlaylistItem.video_id == video_id
-        )
-    )
-    if exists is None:
-        next_pos = (
-            db.scalar(
-                select(func.coalesce(func.max(PlaylistItem.position), -1)).where(
-                    PlaylistItem.playlist_id == pl.id
-                )
-            )
-            + 1
-        )
-        db.add(
-            PlaylistItem(playlist_id=pl.id, video_id=video_id, position=next_pos)
-        )
-        recompute_dirty(db, pl)
-        db.commit()
+    _add_item(db, pl, video_id, mark_dirty=True)
     return {"playlist_id": pl.id, "video_id": video_id}
 
 
diff --git a/backend/app/routes/sync.py b/backend/app/routes/sync.py
index e6fdcc2..0ee9f4e 100644
--- a/backend/app/routes/sync.py
+++ b/backend/app/routes/sync.py
@@ -3,7 +3,7 @@ from sqlalchemy import and_, case, func, select, update
 from sqlalchemy.orm import Session
 
 from app import quota, state
-from app.auth import current_user, has_read_scope, require_human
+from app.auth import admin_user, current_user, has_read_scope, require_human
 from app.db import get_db
 from app.models import Channel, Subscription, User, Video
 from app.sync.runner import (
@@ -40,11 +40,10 @@ def sync_subscriptions(
             status_code=403,
             detail="Connect your YouTube account (read access) to import subscriptions.",
         )
-    before = quota.units_used_today(db)
-    with quota.attribute(user.id, quota.QuotaAction.SUBSCRIPTIONS_PULL):
+    with quota.measured(db, user.id, quota.QuotaAction.SUBSCRIPTIONS_PULL) as m:
         result = import_subscriptions(db, user)
-    result["quota_used_estimate"] = quota.units_used_today(db) - before
-    result["quota_remaining_today"] = quota.remaining_today(db)
+    result["quota_used_estimate"] = m.used
+    result["quota_remaining_today"] = m.remaining
     return result
 
 
@@ -62,10 +61,9 @@ def sync_backfill(
     db: Session = Depends(get_db),
     max_channels: int = 25,
 ) -> dict:
-    before = quota.units_used_today(db)
-    with quota.attribute(user.id, quota.QuotaAction.VIDEOS_BACKFILL_RECENT):
+    with quota.measured(db, user.id, quota.QuotaAction.VIDEOS_BACKFILL_RECENT) as m:
         result = run_recent_backfill(db, _user_channels(db, user), max_channels=max_channels)
-    result["quota_used_estimate"] = quota.units_used_today(db) - before
+    result["quota_used_estimate"] = m.used
     return result
 
 
@@ -73,13 +71,9 @@ def sync_backfill(
 def sync_enrich(
     user: User = Depends(require_human), db: Session = Depends(get_db)
 ) -> dict:
-    before = quota.units_used_today(db)
-    with quota.attribute(user.id, quota.QuotaAction.VIDEOS_ENRICH):
+    with quota.measured(db, user.id, quota.QuotaAction.VIDEOS_ENRICH) as m:
         enriched = run_enrich(db)
-    return {
-        "enriched": enriched,
-        "quota_used_estimate": quota.units_used_today(db) - before,
-    }
+    return {"enriched": enriched, "quota_used_estimate": m.used}
 
 
 @router.get("/status")
@@ -194,20 +188,12 @@ def deep_all(
 
 
 @router.post("/pause")
-def pause_sync(
-    user: User = Depends(current_user), db: Session = Depends(get_db)
-) -> dict:
-    if user.role != "admin":
-        raise HTTPException(status_code=403, detail="Admin only")
+def pause_sync(_: User = Depends(admin_user), db: Session = Depends(get_db)) -> dict:
     state.set_sync_paused(db, True)
     return {"paused": True}
 
 
 @router.post("/resume")
-def resume_sync(
-    user: User = Depends(current_user), db: Session = Depends(get_db)
-) -> dict:
-    if user.role != "admin":
-        raise HTTPException(status_code=403, detail="Admin only")
+def resume_sync(_: User = Depends(admin_user), db: Session = Depends(get_db)) -> dict:
     state.set_sync_paused(db, False)
     return {"paused": False}
diff --git a/backend/app/routes/tags.py b/backend/app/routes/tags.py
index 96aac97..1ba7449 100644
--- a/backend/app/routes/tags.py
+++ b/backend/app/routes/tags.py
@@ -3,7 +3,7 @@ from sqlalchemy import func, or_, select
 from sqlalchemy.exc import IntegrityError
 from sqlalchemy.orm import Session
 
-from app.auth import current_user
+from app.auth import admin_user, current_user
 from app.db import get_db
 from app.models import ChannelTag, Tag, User
 from app.sync.autotag import run_autotag_all
@@ -103,10 +103,8 @@ def delete_tag(
 
 @router.post("/recompute")
 def recompute(
-    user: User = Depends(current_user),
+    _: User = Depends(admin_user),
     db: Session = Depends(get_db),
     only_missing: bool = False,
 ) -> dict:
-    if user.role != "admin":
-        raise HTTPException(status_code=403, detail="Admin only")
     return run_autotag_all(db, only_missing=only_missing)
diff --git a/backend/app/security.py b/backend/app/security.py
index 4693582..fadbbaf 100644
--- a/backend/app/security.py
+++ b/backend/app/security.py
@@ -1,3 +1,5 @@
+import hashlib
+
 from argon2 import PasswordHasher
 from cryptography.fernet import Fernet
 
@@ -7,6 +9,12 @@ from app.config import settings
 _ph = PasswordHasher()
 
 
+def hash_token(raw: str) -> str:
+    """SHA-256 hex digest for storing single-use tokens (email-link tokens, the setup token)
+    by hash rather than in cleartext. Not a password hash — these are high-entropy randoms."""
+    return hashlib.sha256(raw.encode()).hexdigest()
+
+
 def hash_password(password: str) -> str:
     return _ph.hash(password)
 
diff --git a/backend/app/state.py b/backend/app/state.py
index c82f3dc..5466903 100644
--- a/backend/app/state.py
+++ b/backend/app/state.py
@@ -1,5 +1,4 @@
 """Global admin-controlled app state (e.g. pausing background sync, first-run setup)."""
-import hashlib
 import logging
 import secrets
 
@@ -7,6 +6,7 @@ from sqlalchemy.orm import Session
 
 from app.config import settings
 from app.models import AppState
+from app.security import hash_token
 
 log = logging.getLogger("siftlode.state")
 
@@ -73,16 +73,12 @@ def mark_configured(db: Session) -> None:
     log.info("Instance marked configured; setup wizard disabled.")
 
 
-def _hash_token(raw: str) -> str:
-    return hashlib.sha256(raw.encode()).hexdigest()
-
-
 def rotate_setup_token(db: Session) -> str:
     """Generate a fresh one-time setup token, persist only its hash, and return the raw token
     (logged at startup so the admin can open the wizard)."""
     raw = secrets.token_urlsafe(24)
     row = _row(db)
-    row.setup_token_hash = _hash_token(raw)
+    row.setup_token_hash = hash_token(raw)
     db.add(row)
     db.commit()
     return raw
@@ -93,7 +89,7 @@ def check_setup_token(db: Session, raw: str | None) -> bool:
     if not raw:
         return False
     stored = _row(db).setup_token_hash
-    return stored is not None and secrets.compare_digest(stored, _hash_token(raw))
+    return stored is not None and secrets.compare_digest(stored, hash_token(raw))
 
 
 def get_maintenance_batch(db: Session) -> int:
diff --git a/backend/app/sync/maintenance.py b/backend/app/sync/maintenance.py
index 80c0129..1d35003 100644
--- a/backend/app/sync/maintenance.py
+++ b/backend/app/sync/maintenance.py
@@ -20,18 +20,19 @@ Quota: phase 1 costs ~(flagged / 50) units, phase 2 ~(batch / 50). Both respect
 backfill reserve as the other jobs so interactive syncs never starve.
 """
 import logging
-from datetime import datetime, timedelta, timezone
+from datetime import timedelta
 
-from sqlalchemy import or_, select
+from sqlalchemy import select
 from sqlalchemy.orm import Session
 
 from app import progress, quota, sysconfig
 from app.config import settings
-from app.models import Playlist, PlaylistItem, Video, VideoState
+from app.models import Playlist, PlaylistItem, Video
 from app.notifications import create_notification
 from app.state import get_maintenance_batch
 from app.sync.runner import get_service_user
 from app.sync.videos import apply_video_details, parse_dt
+from app.utils import now_utc as _now
 from app.youtube.client import YouTubeClient
 
 log = logging.getLogger("siftlode.maintenance")
@@ -45,10 +46,6 @@ GRACE_DAYS_BY_REASON = {
 DEFAULT_GRACE_DAYS = settings.maintenance_grace_days
 
 
-def _now() -> datetime:
-    return datetime.now(timezone.utc)
-
-
 def _grace_days(reason: str | None) -> int:
     return GRACE_DAYS_BY_REASON.get(reason or "", DEFAULT_GRACE_DAYS)
 
@@ -91,14 +88,9 @@ def _collect_user_impact(db: Session, videos: list[Video]) -> dict[int, list[dic
     impact: dict[int, set[str]] = {}
     if not ids:
         return {}
-    # Saved (VideoState.status == "saved").
-    for user_id, video_id in db.execute(
-        select(VideoState.user_id, VideoState.video_id).where(
-            VideoState.video_id.in_(ids), VideoState.status == "saved"
-        )
-    ):
-        impact.setdefault(user_id, set()).add(video_id)
-    # In any of the user's playlists (covers watch-later, which is a playlist).
+    # Anyone who had it in a playlist — which now also covers "saved": Watch later became a
+    # built-in playlist, so "saved" is no longer a VideoState status (the old status=="saved"
+    # scan matched nothing and under-counted impacted users).
     for user_id, video_id in db.execute(
         select(Playlist.user_id, PlaylistItem.video_id)
         .join(PlaylistItem, PlaylistItem.playlist_id == Playlist.id)
diff --git a/backend/app/sync/playlists.py b/backend/app/sync/playlists.py
index 4dcbaac..547dc55 100644
--- a/backend/app/sync/playlists.py
+++ b/backend/app/sync/playlists.py
@@ -94,6 +94,34 @@ def _ensure_videos(db: Session, yt: YouTubeClient, video_ids: list[str]) -> None
     db.commit()
 
 
+def _replace_items_from_youtube(
+    db: Session, yt: YouTubeClient, pl: Playlist, ids: list[str]
+) -> list[str]:
+    """Mirror a YouTube playlist's ordered video ids into `pl`'s local items (authoritative
+    replace): ensure the videos exist in the catalog, keep only those present in their YT
+    order (de-duplicated), swap the items out, and reset the synced fingerprint + dirty flag.
+    `pl.name` must already be set to the desired name. The caller commits. Returns the final
+    ordered ids."""
+    _ensure_videos(db, yt, ids)
+    present = (
+        set(db.execute(select(Video.id).where(Video.id.in_(ids))).scalars().all())
+        if ids
+        else set()
+    )
+    ordered: list[str] = []
+    seen: set[str] = set()
+    for v in ids:
+        if v in present and v not in seen:
+            seen.add(v)
+            ordered.append(v)
+    db.execute(delete(PlaylistItem).where(PlaylistItem.playlist_id == pl.id))
+    for pos, vid in enumerate(ordered):
+        db.add(PlaylistItem(playlist_id=pl.id, video_id=vid, position=pos))
+    pl.synced_fingerprint = fingerprint(pl.name, ordered)
+    pl.dirty = False
+    return ordered
+
+
 def sync_user_playlists(db: Session, user: User) -> dict:
     """Mirror the user's YouTube playlists into local source='youtube' playlists. Leaves
     the user's local playlists and the built-in Watch later untouched."""
@@ -152,25 +180,9 @@ def sync_user_playlists(db: Session, user: User) -> dict:
                 db.flush()
             else:
                 pl.name = p.get("title") or pl.name
-            ids = list(yt.iter_my_playlist_video_ids(ytid))
-            _ensure_videos(db, yt, ids)
-            present = (
-                set(db.execute(select(Video.id).where(Video.id.in_(ids))).scalars().all())
-                if ids
-                else set()
-            )
-            ordered: list[str] = []
-            seen: set[str] = set()
-            for v in ids:
-                if v in present and v not in seen:
-                    seen.add(v)
-                    ordered.append(v)
             # Mirror is authoritative: replace the items to match YouTube's order.
-            db.execute(delete(PlaylistItem).where(PlaylistItem.playlist_id == pl.id))
-            for pos, vid in enumerate(ordered):
-                db.add(PlaylistItem(playlist_id=pl.id, video_id=vid, position=pos))
-            pl.synced_fingerprint = fingerprint(pl.name, ordered)
-            pl.dirty = False
+            ids = list(yt.iter_my_playlist_video_ids(ytid))
+            _replace_items_from_youtube(db, yt, pl, ids)
             db.commit()
             synced += 1
     return {"synced": synced}
@@ -349,25 +361,9 @@ def repull_playlist(db: Session, user: User, pl: Playlist) -> dict:
         snippet = yt.get_playlist_snippet(pl.yt_playlist_id)
         if snippet is None:
             raise YouTubeError("Playlist no longer exists on YouTube")
-        ids = list(yt.iter_my_playlist_video_ids(pl.yt_playlist_id))
-        _ensure_videos(db, yt, ids)
-        present = (
-            set(db.execute(select(Video.id).where(Video.id.in_(ids))).scalars().all())
-            if ids
-            else set()
-        )
-        ordered: list[str] = []
-        seen: set[str] = set()
-        for v in ids:
-            if v in present and v not in seen:
-                seen.add(v)
-                ordered.append(v)
         pl.name = snippet.get("title") or pl.name
-        db.execute(delete(PlaylistItem).where(PlaylistItem.playlist_id == pl.id))
-        for pos, vid in enumerate(ordered):
-            db.add(PlaylistItem(playlist_id=pl.id, video_id=vid, position=pos))
-        pl.synced_fingerprint = fingerprint(pl.name, ordered)
-        pl.dirty = False
+        ids = list(yt.iter_my_playlist_video_ids(pl.yt_playlist_id))
+        ordered = _replace_items_from_youtube(db, yt, pl, ids)
         db.commit()
     return {"items": len(ordered)}
 
diff --git a/backend/app/utils.py b/backend/app/utils.py
new file mode 100644
index 0000000..70feb39
--- /dev/null
+++ b/backend/app/utils.py
@@ -0,0 +1,17 @@
+"""Small cross-cutting helpers shared across modules (kept dependency-light on purpose)."""
+import re
+from datetime import datetime, timezone
+
+# Single source of truth for "looks like an email" — used by every endpoint that accepts an
+# address (auth register/reset/demo, admin invites + demo whitelist, the setup wizard). Keep
+# the strictness in one place so routes don't drift between this and a looser "@"-in check.
+_EMAIL_RE = re.compile(r"^[^@\s]+@[^@\s]+\.[^@\s]+$")
+
+
+def valid_email(value: str | None) -> bool:
+    return bool(value and _EMAIL_RE.match(value))
+
+
+def now_utc() -> datetime:
+    """Current time as a timezone-aware UTC datetime."""
+    return datetime.now(timezone.utc)
diff --git a/frontend/src/App.tsx b/frontend/src/App.tsx
index 2176d6a..3e3ee64 100644
--- a/frontend/src/App.tsx
+++ b/frontend/src/App.tsx
@@ -19,6 +19,7 @@ import {
 } from "./lib/sidebarLayout";
 import { configureNotifications, getNotifSettings, notify, removeByMetaKind, type NotifSettings } from "./lib/notifications";
 import { hintsEnabled, setHintsEnabled } from "./lib/hints";
+import { LS, readMerged, usePersistedState } from "./lib/storage";
 import { useConfirm } from "./components/ConfirmProvider";
 import type { PrefsController } from "./components/SettingsPanel";
 import Welcome from "./components/Welcome";
@@ -59,9 +60,9 @@ const DEFAULT_FILTERS: FeedFilters = {
   show: "unwatched",
 };
 
-const FILTERS_KEY = "siftlode.filters";
-const PAGE_KEY = "siftlode.page";
-const PERF_KEY = "siftlode.perfMode";
+const FILTERS_KEY = LS.filters;
+const PAGE_KEY = LS.page;
+const PERF_KEY = LS.perfMode;
 
 // The preferences edited on the Settings page. They apply locally for instant preview but
 // persist to the server only on an explicit Save — so App holds both the live "draft" (the
@@ -84,11 +85,7 @@ function loadInitialPage(): Page {
 }
 
 function loadStoredFilters(): FeedFilters {
-  try {
-    return { ...DEFAULT_FILTERS, ...JSON.parse(localStorage.getItem(FILTERS_KEY) || "{}") };
-  } catch {
-    return DEFAULT_FILTERS;
-  }
+  return readMerged(FILTERS_KEY, DEFAULT_FILTERS);
 }
 
 // URL wins over localStorage so a pasted link reproduces the exact view.
@@ -126,18 +123,13 @@ export default function App() {
   const [sidebarLayout, setSidebarLayoutState] = useState<SidebarLayout>(loadLayout);
   const [page, setPageState] = useState<Page>(loadInitialPage);
   const [wizardOpen, setWizardOpen] = useState(false);
-  const CHANNEL_FILTER_KEY = "siftlode.channelFilter";
-  const [channelFilter, setChannelFilterState] = useState<ChannelStatusFilter>(() => {
-    const v = localStorage.getItem(CHANNEL_FILTER_KEY);
-    return v === "needs_full" || v === "fully_synced" || v === "hidden" || v === "all"
-      ? v
-      : "all";
-  });
-  // Persist the channel status chip so a reload (F5) keeps it.
-  const setChannelFilter = (f: ChannelStatusFilter) => {
-    setChannelFilterState(f);
-    localStorage.setItem(CHANNEL_FILTER_KEY, f);
-  };
+  // Channel status chip, persisted so a reload (F5) keeps it; clamp a stale value at render.
+  const [channelFilterRaw, setChannelFilter] = usePersistedState(LS.channelFilter, "all");
+  const channelFilter: ChannelStatusFilter = (
+    ["needs_full", "fully_synced", "hidden", "all"] as const
+  ).includes(channelFilterRaw as ChannelStatusFilter)
+    ? (channelFilterRaw as ChannelStatusFilter)
+    : "all";
   const [aboutOpen, setAboutOpen] = useState(false);
   const [notesOpen, setNotesOpen] = useState(false);
   const [notesHighlight, setNotesHighlight] = useState<string | undefined>(undefined);
@@ -145,14 +137,9 @@ export default function App() {
   // persisted so navigation intents that target the subscriptions table — the header's
   // "without full history" link, focus-channel — can force it back to "subscribed" instead
   // of dumping the user on whatever tab they last left open.
-  const CHANNELS_VIEW_KEY = "siftlode.channelsView";
-  const [channelsView, setChannelsViewState] = useState<ChannelsView>(() =>
-    localStorage.getItem(CHANNELS_VIEW_KEY) === "discovery" ? "discovery" : "subscribed"
-  );
-  const setChannelsView = (v: ChannelsView) => {
-    setChannelsViewState(v);
-    localStorage.setItem(CHANNELS_VIEW_KEY, v);
-  };
+  const [channelsViewRaw, setChannelsView] = usePersistedState(LS.channelsView, "subscribed");
+  const channelsView: ChannelsView =
+    channelsViewRaw === "discovery" ? "discovery" : "subscribed";
   // Bumped to tell the channel manager to drop a stale column filter when we send the user
   // there to see a specific set (the header's "without full history" link).
   const [channelsFilterReset, setChannelsFilterReset] = useState(0);
@@ -318,7 +305,7 @@ export default function App() {
     if (result === "ok") {
       notify({ level: "success", message: t("settings.account.googleLink.linked") });
       void meQuery.refetch();
-      localStorage.setItem("siftlode.settingsTab", "account");
+      localStorage.setItem(LS.settingsTab, "account");
       setPage("settings");
     } else {
       const key = result === "conflict" || result === "mismatch" ? result : "error";
diff --git a/frontend/src/components/AddToPlaylist.tsx b/frontend/src/components/AddToPlaylist.tsx
index 5260163..a3b174e 100644
--- a/frontend/src/components/AddToPlaylist.tsx
+++ b/frontend/src/components/AddToPlaylist.tsx
@@ -4,6 +4,7 @@ import { useTranslation } from "react-i18next";
 import { useQuery, useQueryClient } from "@tanstack/react-query";
 import { Check, ListPlus, Plus, Youtube } from "lucide-react";
 import { api, type Playlist } from "../lib/api";
+import { useDismiss } from "../lib/useDismiss";
 
 // A small popover (portaled to body, so the feed grid can't clip it) for toggling a
 // video's membership in the user's playlists, with inline "new playlist" creation.
@@ -59,25 +60,13 @@ export default function AddToPlaylist({
     setOpen((o) => !o);
   }
 
+  useDismiss(open, () => setOpen(false), [panelRef, triggerRef]);
+  // Keep the panel anchored to the trigger as the page resizes/scrolls while open.
   useEffect(() => {
     if (!open) return;
-    function onDoc(e: MouseEvent) {
-      if (
-        !panelRef.current?.contains(e.target as Node) &&
-        !triggerRef.current?.contains(e.target as Node)
-      )
-        setOpen(false);
-    }
-    function onKey(e: KeyboardEvent) {
-      if (e.key === "Escape") setOpen(false);
-    }
-    document.addEventListener("mousedown", onDoc);
-    document.addEventListener("keydown", onKey);
     window.addEventListener("resize", place);
     window.addEventListener("scroll", place, true);
     return () => {
-      document.removeEventListener("mousedown", onDoc);
-      document.removeEventListener("keydown", onKey);
       window.removeEventListener("resize", place);
       window.removeEventListener("scroll", place, true);
     };
diff --git a/frontend/src/components/AdminUsers.tsx b/frontend/src/components/AdminUsers.tsx
index e90b8e5..356b99d 100644
--- a/frontend/src/components/AdminUsers.tsx
+++ b/frontend/src/components/AdminUsers.tsx
@@ -4,7 +4,9 @@ import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
 import { Ban, Check, RotateCcw, Shield, Trash2, UserPlus, X } from "lucide-react";
 import { api, type AdminUserRow, type Invite, type Me } from "../lib/api";
 import { notify } from "../lib/notifications";
+import { LS } from "../lib/storage";
 import Tooltip from "./Tooltip";
+import { Section } from "./ui/form";
 import { useConfirm } from "./ConfirmProvider";
 import Tabs, { usePersistedTab } from "./Tabs";
 
@@ -14,7 +16,7 @@ import Tabs, { usePersistedTab } from "./Tabs";
 // The persisted-tab storage key + the access-requests tab id, exported so a notification's
 // "Review" link can pre-select that tab before navigating here (usePersistedTab reads the key
 // on mount, and this page mounts fresh on navigation).
-export const ADMIN_USERS_TAB_KEY = "siftlode.adminUsersTab";
+export const ADMIN_USERS_TAB_KEY = LS.adminUsersTab;
 export const ADMIN_USERS_ACCESS_TAB = "access";
 
 export function focusAccessRequestsTab(): void {
@@ -40,15 +42,6 @@ export default function AdminUsers({ me }: { me: Me }) {
   );
 }
 
-function Section({ title, children }: { title: string; children: React.ReactNode }) {
-  return (
-    <div className="glass rounded-2xl p-4 mb-4">
-      <div className="text-xs uppercase tracking-wide text-muted mb-3">{title}</div>
-      {children}
-    </div>
-  );
-}
-
 function Badge({ tone, children }: { tone: "accent" | "muted" | "warning"; children: React.ReactNode }) {
   const cls =
     tone === "accent"
@@ -137,7 +130,7 @@ function UsersRoles({ me }: { me: Me }) {
   const rows = q.data ?? [];
 
   return (
-    <Section title={t("users.roles.title")}>
+    <Section card title={t("users.roles.title")}>
       <p className="text-xs text-muted leading-relaxed mb-3">{t("users.roles.intro")}</p>
       {rows.length === 0 ? (
         <p className="text-sm text-muted">{t("users.roles.empty")}</p>
@@ -265,7 +258,7 @@ function AdminInvites() {
   const decided = list.filter((i) => i.status !== "pending");
 
   return (
-    <Section title={t("settings.invites.title")}>
+    <Section card title={t("settings.invites.title")}>
       {pending.length === 0 ? (
         <p className="text-sm text-muted">{t("settings.invites.noPending")}</p>
       ) : (
@@ -359,7 +352,7 @@ function AdminDemo() {
   const rows = list.data ?? [];
 
   return (
-    <Section title={t("settings.demo.title")}>
+    <Section card title={t("settings.demo.title")}>
       <p className="text-xs text-muted leading-relaxed mb-2">{t("settings.demo.intro")}</p>
 
       {rows.length > 0 && (
diff --git a/frontend/src/components/Channels.tsx b/frontend/src/components/Channels.tsx
index ddcdfa4..21cce00 100644
--- a/frontend/src/components/Channels.tsx
+++ b/frontend/src/components/Channels.tsx
@@ -1,4 +1,4 @@
-import { useEffect, useRef, useState } from "react";
+import { useRef, useState } from "react";
 import { Trans, useTranslation } from "react-i18next";
 import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
 import {
@@ -14,7 +14,8 @@ import {
   UserMinus,
 } from "lucide-react";
 import { api, HttpError, type ManagedChannel, type Tag } from "../lib/api";
-import { formatEta, formatViews, relativeTime } from "../lib/format";
+import { useDismiss } from "../lib/useDismiss";
+import { formatEta, formatTotalHours, formatViews, relativeTime } from "../lib/format";
 import { notify } from "../lib/notifications";
 import Tooltip from "./Tooltip";
 import DataTable, { type Column } from "./DataTable";
@@ -27,13 +28,6 @@ export type ChannelsView = "subscribed" | "discovery";
 
 export type ChannelStatusFilter = "all" | "needs_full" | "fully_synced" | "hidden";
 
-// Compact total-duration label for a whole channel (hours-scale, so H:MM:SS would be huge).
-function fmtTotalDuration(sec: number): string {
-  if (!sec) return "—";
-  const h = Math.round(sec / 3600);
-  return h >= 1 ? `${h.toLocaleString()} h` : `${Math.max(1, Math.round(sec / 60))} m`;
-}
-
 const STATUS_FILTERS: { id: ChannelStatusFilter; labelKey: string }[] = [
   { id: "all", labelKey: "channels.filters.all" },
   { id: "needs_full", labelKey: "channels.filters.needsFull" },
@@ -286,7 +280,7 @@ export default function Channels({
       nowrap: true,
       sortable: true,
       sortValue: (c) => c.total_duration_seconds,
-      render: (c) => <span className="text-muted tabular-nums">{fmtTotalDuration(c.total_duration_seconds)}</span>,
+      render: (c) => <span className="text-muted tabular-nums">{formatTotalHours(c.total_duration_seconds)}</span>,
     },
     {
       key: "types",
@@ -616,19 +610,7 @@ function TagsCell({
   const { t } = useTranslation();
   const [open, setOpen] = useState(false);
   const ref = useRef<HTMLDivElement | null>(null);
-  useEffect(() => {
-    if (!open) return;
-    const onDown = (e: MouseEvent) => {
-      if (!ref.current?.contains(e.target as Node)) setOpen(false);
-    };
-    const onKey = (e: KeyboardEvent) => e.key === "Escape" && setOpen(false);
-    document.addEventListener("mousedown", onDown);
-    document.addEventListener("keydown", onKey);
-    return () => {
-      document.removeEventListener("mousedown", onDown);
-      document.removeEventListener("keydown", onKey);
-    };
-  }, [open]);
+  useDismiss(open, () => setOpen(false), ref);
   if (userTags.length === 0) return null;
   // Show only the tags actually attached to this channel; the “+” opens a per-channel
   // picker to attach/detach (kept the convenient "kirakás" without listing every tag
diff --git a/frontend/src/components/ConfigPanel.tsx b/frontend/src/components/ConfigPanel.tsx
index 1da0e7a..fad57be 100644
--- a/frontend/src/components/ConfigPanel.tsx
+++ b/frontend/src/components/ConfigPanel.tsx
@@ -1,11 +1,13 @@
 import { useEffect, useMemo, useState } from "react";
 import { useTranslation } from "react-i18next";
 import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
-import { Check, RotateCcw, Save, Send } from "lucide-react";
+import { RotateCcw, Send } from "lucide-react";
 import { api, type ConfigItem } from "../lib/api";
 import { notify } from "../lib/notifications";
 import Tooltip from "./Tooltip";
 import Tabs, { usePersistedTab } from "./Tabs";
+import { Switch } from "./ui/form";
+import { DraftSaveBar } from "./ui/DraftSaveBar";
 
 // Admin Configuration page: edit DB-overridable operational settings (registry-driven from the
 // backend — adding a key there makes it appear here automatically). Edits are drafted and
@@ -150,40 +152,21 @@ export default function ConfigPanel() {
         </div>
       )}
 
-      {(dirty || saveState !== "idle") && (
-        <div className="fixed bottom-4 left-1/2 -translate-x-1/2 z-40 glass rounded-2xl shadow-lg flex items-center justify-between gap-4 px-4 py-3 w-[min(48rem,calc(100%-2rem))]">
-          <span className="text-sm text-muted">
-            {saveState === "saved" ? (
-              <span className="text-emerald-500 inline-flex items-center gap-1.5">
-                <Check className="w-4 h-4" />
-                {t("config.saved")}
-              </span>
-            ) : saveState === "error" ? (
-              <span className="text-red-500">{t("config.saveFailed")}</span>
-            ) : (
-              t("config.unsaved")
-            )}
-          </span>
-          <div className="flex items-center gap-2">
-            <button
-              onClick={discard}
-              disabled={saveState === "saving" || !dirty}
-              className="glass-card glass-hover flex items-center gap-1.5 px-3 py-1.5 rounded-lg text-sm disabled:opacity-40 transition"
-            >
-              <RotateCcw className="w-4 h-4" />
-              {t("config.discard")}
-            </button>
-            <button
-              onClick={save}
-              disabled={saveState === "saving" || !dirty}
-              className="flex items-center gap-1.5 px-3 py-1.5 rounded-lg text-sm bg-accent text-accent-fg font-medium shadow-md shadow-accent/20 disabled:opacity-40 transition"
-            >
-              <Save className="w-4 h-4" />
-              {saveState === "saving" ? t("config.saving") : t("config.save")}
-            </button>
-          </div>
-        </div>
-      )}
+      <DraftSaveBar
+        variant="floating"
+        dirty={dirty}
+        state={saveState}
+        onSave={save}
+        onDiscard={discard}
+        labels={{
+          saved: t("config.saved"),
+          failed: t("config.saveFailed"),
+          unsaved: t("config.unsaved"),
+          discard: t("config.discard"),
+          save: t("config.save"),
+          saving: t("config.saving"),
+        }}
+      />
     </div>
   );
 }
@@ -241,7 +224,7 @@ function Field({
 
       <div className="flex flex-col items-end gap-1.5 shrink-0">
         {isBool ? (
-          <Toggle checked={value === "true"} onChange={(v) => onChange(v ? "true" : "false")} />
+          <Switch checked={value === "true"} onChange={(v) => onChange(v ? "true" : "false")} />
         ) : (
           <input
             type={item.secret ? "password" : isNum ? "number" : "text"}
@@ -272,20 +255,4 @@ function Field({
       </div>
     </div>
   );
-}
-
-function Toggle({ checked, onChange }: { checked: boolean; onChange: (v: boolean) => void }) {
-  return (
-    <button
-      type="button"
-      onClick={() => onChange(!checked)}
-      className={`w-9 h-5 rounded-full transition relative shrink-0 ${checked ? "bg-accent" : "bg-border"}`}
-    >
-      <span
-        className={`absolute top-0.5 w-4 h-4 rounded-full bg-white shadow transition-all ${
-          checked ? "left-[18px]" : "left-0.5"
-        }`}
-      />
-    </button>
-  );
-}
+}
\ No newline at end of file
diff --git a/frontend/src/components/DataTable.tsx b/frontend/src/components/DataTable.tsx
index cad982d..8b9404c 100644
--- a/frontend/src/components/DataTable.tsx
+++ b/frontend/src/components/DataTable.tsx
@@ -1,6 +1,7 @@
 import { useEffect, useRef, useState, type ReactNode } from "react";
 import { useTranslation } from "react-i18next";
 import { ArrowDown, ArrowUp, ChevronLeft, ChevronRight, ListFilter, X } from "lucide-react";
+import { useDismiss } from "../lib/useDismiss";
 
 // A reusable, client-side data table: per-column sort + filter (in the header) + pagination,
 // with its sort/filter/page state optionally persisted to localStorage so a reload (F5) keeps
@@ -121,21 +122,7 @@ export default function DataTable<T>({
     setPage(0);
   }, [resetFiltersToken]);
 
-  useEffect(() => {
-    if (!openFilter) return;
-    function onDown(e: MouseEvent) {
-      if (!popRef.current?.contains(e.target as Node)) setOpenFilter(null);
-    }
-    function onKey(e: KeyboardEvent) {
-      if (e.key === "Escape") setOpenFilter(null);
-    }
-    document.addEventListener("mousedown", onDown);
-    document.addEventListener("keydown", onKey);
-    return () => {
-      document.removeEventListener("mousedown", onDown);
-      document.removeEventListener("keydown", onKey);
-    };
-  }, [openFilter]);
+  useDismiss(!!openFilter, () => setOpenFilter(null), popRef);
 
   const filtered = rows.filter((row) =>
     columns.every((col) => {
diff --git a/frontend/src/components/Messages.tsx b/frontend/src/components/Messages.tsx
index 0e514be..1ebdc06 100644
--- a/frontend/src/components/Messages.tsx
+++ b/frontend/src/components/Messages.tsx
@@ -22,7 +22,9 @@ export default function Messages({ meId }: { meId: number }) {
   // the module (open() pushes an entry; back() = history.back()).
   const { view, open, back } = useHistorySubview<View>("list");
 
-  if (typeof view === "object") {
+  // Guard against a stale sub-view whose partnerId is the current user's own id (you can't
+  // message yourself). This can be inherited across an account switch — fall back to the list.
+  if (typeof view === "object" && view.partnerId !== meId) {
     return (
       <PageThread
         meId={meId}
diff --git a/frontend/src/components/NavSidebar.tsx b/frontend/src/components/NavSidebar.tsx
index 1822a3e..c3ef325 100644
--- a/frontend/src/components/NavSidebar.tsx
+++ b/frontend/src/components/NavSidebar.tsx
@@ -23,6 +23,7 @@ import {
 import { api, type Me } from "../lib/api";
 import { useLiveQuery } from "../lib/useLiveQuery";
 import { getUnreadCount, subscribe } from "../lib/notifications";
+import { LS } from "../lib/storage";
 import type { Page } from "../lib/urlState";
 import { type LangCode } from "../i18n";
 import AvatarImg from "./Avatar";
@@ -48,7 +49,7 @@ export default function NavSidebar({
 }) {
   const { t } = useTranslation();
   const [collapsed, setCollapsed] = useState<boolean>(
-    () => localStorage.getItem("siftlode.navCollapsed") === "1"
+    () => localStorage.getItem(LS.navCollapsed) === "1"
   );
   const [acctOpen, setAcctOpen] = useState(false);
   const acctBtnRef = useRef<HTMLButtonElement | null>(null);
@@ -90,7 +91,7 @@ export default function NavSidebar({
   function toggleCollapsed() {
     setCollapsed((c) => {
       const next = !c;
-      localStorage.setItem("siftlode.navCollapsed", next ? "1" : "0");
+      localStorage.setItem(LS.navCollapsed, next ? "1" : "0");
       return next;
     });
   }
@@ -111,6 +112,14 @@ export default function NavSidebar({
   async function switchTo(id: number) {
     try {
       await api.switchAccount(id);
+      // Drop the previous account's in-module sub-view/overlay before the reload (which would
+      // otherwise preserve history.state across the swap). Otherwise the new account lands on a
+      // stale sub-view — e.g. an open chat thread whose partnerId belongs to the OLD identity
+      // (often the new account's own id → an empty self-thread). Start at the module root instead.
+      const st = { ...(window.history.state || {}) };
+      delete st._sub;
+      delete st._ov;
+      window.history.replaceState(st, "");
       location.reload(); // cleanest way to reload all per-user state for the new account
     } catch {
       /* a revoked/removed account — leave the popover open */
diff --git a/frontend/src/components/NotificationsPanel.tsx b/frontend/src/components/NotificationsPanel.tsx
index 044074d..8844da3 100644
--- a/frontend/src/components/NotificationsPanel.tsx
+++ b/frontend/src/components/NotificationsPanel.tsx
@@ -19,7 +19,7 @@ import {
   type VideoHiddenMeta,
   type VideoWatchedMeta,
 } from "../lib/notifications";
-import { channelYouTubeUrl } from "../lib/format";
+import { channelYouTubeUrl, relativeFromMs, relativeTime } from "../lib/format";
 import type { Page } from "../lib/urlState";
 import { LEVEL_STYLE } from "./Toaster";
 
@@ -29,22 +29,6 @@ import { LEVEL_STYLE } from "./Toaster";
 // there's one indicator and one place to look. Transient toasts still pop via the Toaster.
 const POLL_MS = 8000;
 
-function relativeTime(iso: string | null, t: (k: string, o?: any) => string): string {
-  if (!iso) return "";
-  return relativeFromMs(new Date(iso).getTime(), t);
-}
-
-function relativeFromMs(ms: number, t: (k: string, o?: any) => string): string {
-  const secs = Math.max(0, Math.round((Date.now() - ms) / 1000));
-  // Reuse the bell's relative-time strings (notifications.time.*) — same format, no dupes.
-  if (secs < 60) return t("notifications.time.justNow");
-  const mins = Math.round(secs / 60);
-  if (mins < 60) return t("notifications.time.minutes", { count: mins });
-  const hours = Math.round(mins / 60);
-  if (hours < 24) return t("notifications.time.hours", { count: hours });
-  return t("notifications.time.days", { count: Math.round(hours / 24) });
-}
-
 export default function NotificationsPanel({
   filters,
   setFilters,
@@ -253,7 +237,7 @@ function NotificationRow({
         <div className="flex items-baseline gap-2">
           <span className="font-medium text-sm">{title}</span>
           <span className="text-[11px] text-muted shrink-0">
-            {relativeTime(n.created_at, t)}
+            {relativeTime(n.created_at)}
           </span>
         </div>
         {body && <div className="text-sm text-muted mt-0.5">{body}</div>}
@@ -338,7 +322,7 @@ function ClientActivityRow({
         {n.title && <div className="text-sm font-semibold">{n.title}</div>}
         <div className="text-sm break-words">{n.message}</div>
         <div className="flex items-center gap-2 mt-0.5">
-          <span className="text-[11px] text-muted">{relativeFromMs(n.ts, t)}</span>
+          <span className="text-[11px] text-muted">{relativeFromMs(n.ts)}</span>
           {needsAction && (
             <span className="text-[10px] uppercase tracking-wide font-semibold text-accent">
               {t("notifications.actionNeeded")}
diff --git a/frontend/src/components/PlayerModal.tsx b/frontend/src/components/PlayerModal.tsx
index fcbc7bb..88a1483 100644
--- a/frontend/src/components/PlayerModal.tsx
+++ b/frontend/src/components/PlayerModal.tsx
@@ -1,6 +1,5 @@
-import { useEffect, useRef, useState, type ReactNode } from "react";
+import { useEffect, useRef, useState } from "react";
 import { useTranslation } from "react-i18next";
-import type { TFunction } from "i18next";
 import { createPortal } from "react-dom";
 import { useQuery, useQueryClient } from "@tanstack/react-query";
 import { AlertTriangle, ArrowLeft, Check, CheckCheck, ExternalLink, SkipBack, SkipForward, X } from "lucide-react";
@@ -8,152 +7,9 @@ import Avatar from "./Avatar";
 import AddToPlaylist from "./AddToPlaylist";
 import { api, type Video } from "../lib/api";
 import { channelYouTubeUrl, formatDuration, formatViews, relativeTime } from "../lib/format";
+import { renderDescription } from "../lib/descriptionLinks";
 import { useBackToClose } from "../lib/history";
 
-// Turn a description into clickable nodes:
-//  - bare timestamps (mm:ss / hh:mm:ss) → seek the inline player
-//  - a YouTube link to the *current* video → seek (to its t= if any)
-//  - a YouTube link to *another* video → load it in the inline player
-//  - emails → mailto:, hashtags → YouTube's hashtag page, other URLs → new tab
-const URL_RE = /(https?:\/\/[^\s<>]+)/g;
-// One pass over plain text for the three inline token kinds (email | hashtag | timestamp).
-const INLINE_RE =
-  /([A-Za-z0-9._%+-]+@[A-Za-z0-9-]+\.[A-Za-z0-9.-]+)|(#[\p{L}\p{N}_]+)|(\b(?:\d{1,2}:)?\d{1,2}:\d{2}\b)/gu;
-
-function tsToSeconds(ts: string): number {
-  const parts = ts.split(":").map((n) => parseInt(n, 10));
-  return parts.length === 3
-    ? parts[0] * 3600 + parts[1] * 60 + parts[2]
-    : parts[0] * 60 + parts[1];
-}
-
-// Parse a YouTube `t`/`start` param: "90", "90s", or "1h2m3s".
-function parseStart(t: string | null): number | null {
-  if (!t) return null;
-  if (/^\d+$/.test(t)) return parseInt(t, 10) || null;
-  const m = t.match(/^(?:(\d+)h)?(?:(\d+)m)?(?:(\d+)s)?$/);
-  if (!m) return null;
-  const total =
-    parseInt(m[1] || "0", 10) * 3600 +
-    parseInt(m[2] || "0", 10) * 60 +
-    parseInt(m[3] || "0", 10);
-  return total || null;
-}
-
-// Extract a video id (+ optional start) from a YouTube URL, else null.
-function parseYouTube(url: string): { id: string; start: number | null } | null {
-  let u: URL;
-  try {
-    u = new URL(url);
-  } catch {
-    return null;
-  }
-  const host = u.hostname.replace(/^www\./, "");
-  let id: string | null = null;
-  if (host === "youtu.be") {
-    id = u.pathname.slice(1) || null;
-  } else if (host === "youtube.com" || host === "m.youtube.com" || host === "music.youtube.com") {
-    if (u.pathname === "/watch") id = u.searchParams.get("v");
-    else {
-      const m = u.pathname.match(/^\/(?:shorts|embed|live)\/([^/?#]+)/);
-      if (m) id = m[1];
-    }
-  }
-  if (!id) return null;
-  return { id, start: parseStart(u.searchParams.get("t") || u.searchParams.get("start")) };
-}
-
-function renderDescription(
-  text: string,
-  opts: {
-    currentId: string;
-    onSeek: (seconds: number) => void;
-    onLoadVideo: (id: string, start: number | null) => void;
-    t: TFunction;
-  }
-): ReactNode[] {
-  const { t } = opts;
-  const out: ReactNode[] = [];
-  let key = 0;
-  const linkCls = "text-accent hover:underline break-all";
-  // Tidy YouTube descriptions: drop trailing spaces and remove blank lines entirely
-  // (they're just noise in the popover), keeping single line breaks.
-  const clean = text.replace(/[ \t]+\n/g, "\n").replace(/\n{2,}/g, "\n").trim();
-  for (const chunk of clean.split(URL_RE)) {
-    if (/^https?:\/\//.test(chunk)) {
-      const href = chunk.replace(/[.,;:!?)\]]+$/, "");
-      const yt = parseYouTube(href);
-      if (yt) {
-        const sameVideo = yt.id === opts.currentId;
-        out.push(
-          <button
-            key={key++}
-            onClick={() =>
-              sameVideo ? opts.onSeek(yt.start ?? 0) : opts.onLoadVideo(yt.id, yt.start)
-            }
-            className={linkCls}
-            title={sameVideo ? t("player.jumpToTime") : t("player.playInApp")}
-          >
-            {href}
-          </button>
-        );
-      } else {
-        out.push(
-          <a key={key++} href={href} target="_blank" rel="noreferrer" className={linkCls}>
-            {href}
-          </a>
-        );
-      }
-      continue;
-    }
-    // Plain text: pull out emails, hashtags and bare timestamps.
-    INLINE_RE.lastIndex = 0;
-    let last = 0;
-    let m: RegExpExecArray | null;
-    while ((m = INLINE_RE.exec(chunk))) {
-      if (m.index > last) out.push(<span key={key++}>{chunk.slice(last, m.index)}</span>);
-      if (m[1]) {
-        // Email — trim trailing punctuation the domain rule may have swallowed.
-        const email = m[1].replace(/[.,;:]+$/, "");
-        out.push(
-          <a key={key++} href={`mailto:${email}`} className={linkCls}>
-            {email}
-          </a>
-        );
-        if (m[1].length > email.length) out.push(<span key={key++}>{m[1].slice(email.length)}</span>);
-      } else if (m[2]) {
-        // Hashtag → YouTube's hashtag feed (mirrors native YouTube behavior).
-        const tag = m[2].slice(1);
-        out.push(
-          <a
-            key={key++}
-            href={`https://www.youtube.com/hashtag/${encodeURIComponent(tag)}`}
-            target="_blank"
-            rel="noreferrer"
-            className={linkCls}
-          >
-            {m[2]}
-          </a>
-        );
-      } else {
-        const ts = m[3];
-        out.push(
-          <button
-            key={key++}
-            onClick={() => opts.onSeek(tsToSeconds(ts))}
-            className="text-accent hover:underline"
-          >
-            {ts}
-          </button>
-        );
-      }
-      last = m.index + m[0].length;
-    }
-    if (last < chunk.length) out.push(<span key={key++}>{chunk.slice(last)}</span>);
-  }
-  return out;
-}
-
 // Experiment (branch experiment/inline-player): play the video in-app via the
 // YouTube IFrame Player API (not a bare embed) so we can read playback position
 // and resume where the user left off. The modal closes via the in-card Close
diff --git a/frontend/src/components/Playlists.tsx b/frontend/src/components/Playlists.tsx
index 8c49f64..dbdba96 100644
--- a/frontend/src/components/Playlists.tsx
+++ b/frontend/src/components/Playlists.tsx
@@ -37,6 +37,7 @@ import {
 import { api, type Playlist, type Video } from "../lib/api";
 import { formatDuration } from "../lib/format";
 import { notify } from "../lib/notifications";
+import { LS, readMerged, writeJSON } from "../lib/storage";
 import { useUndoable } from "../lib/useUndoable";
 import PlayerModal from "./PlayerModal";
 import UndoToolbar from "./UndoToolbar";
@@ -187,26 +188,18 @@ export default function Playlists({ canWrite }: { canWrite: boolean }) {
   const confirm = useConfirm();
   // Persist the selected playlist so F5 keeps it (the de-URL refactor dropped it from the URL).
   const [selectedId, setSelectedId] = useState<number | null>(() => {
-    const s = localStorage.getItem("siftlode.playlist");
+    const s = localStorage.getItem(LS.playlist);
     return s ? Number(s) : null;
   });
   useEffect(() => {
-    if (selectedId != null) localStorage.setItem("siftlode.playlist", String(selectedId));
+    if (selectedId != null) localStorage.setItem(LS.playlist, String(selectedId));
   }, [selectedId]);
   const selectedRef = useRef<HTMLButtonElement | null>(null);
   const scrolledRef = useRef(false);
   // How the left playlist rail is ordered (persisted).
-  const [plSort, setPlSort] = useState<PlSort>(() => {
-    try {
-      const s = localStorage.getItem("siftlode.plSort");
-      if (s) return { ...PL_SORT_DEFAULT, ...JSON.parse(s) };
-    } catch {
-      /* ignore */
-    }
-    return PL_SORT_DEFAULT;
-  });
+  const [plSort, setPlSort] = useState<PlSort>(() => readMerged(LS.plSort, PL_SORT_DEFAULT));
   useEffect(() => {
-    localStorage.setItem("siftlode.plSort", JSON.stringify(plSort));
+    writeJSON(LS.plSort, plSort);
   }, [plSort]);
   const [newName, setNewName] = useState("");
   const [renaming, setRenaming] = useState(false);
diff --git a/frontend/src/components/Scheduler.tsx b/frontend/src/components/Scheduler.tsx
index 5a2556d..394434a 100644
--- a/frontend/src/components/Scheduler.tsx
+++ b/frontend/src/components/Scheduler.tsx
@@ -1,5 +1,6 @@
 import { useEffect, useState } from "react";
 import { useTranslation } from "react-i18next";
+import i18n from "../i18n";
 import { useMutation, useQueryClient } from "@tanstack/react-query";
 import {
   Activity,
@@ -31,7 +32,7 @@ function secsUntil(iso: string | null): number | null {
 }
 
 function fmtCountdown(s: number): string {
-  if (s <= 0) return "now";
+  if (s <= 0) return i18n.t("time.eta.now");
   if (s < 60) return `${s}s`;
   const m = Math.floor(s / 60);
   if (m < 60) return `${m}m ${s % 60}s`;
diff --git a/frontend/src/components/SettingsPanel.tsx b/frontend/src/components/SettingsPanel.tsx
index 156225f..4d13622 100644
--- a/frontend/src/components/SettingsPanel.tsx
+++ b/frontend/src/components/SettingsPanel.tsx
@@ -1,12 +1,15 @@
 import { useState } from "react";
 import { useTranslation } from "react-i18next";
 import { useQueryClient } from "@tanstack/react-query";
-import { Bell, Check, Monitor, RotateCcw, Save, Trash2, User } from "lucide-react";
+import { Bell, Monitor, Trash2, User } from "lucide-react";
 import { SCHEMES, type Scheme, type ThemePrefs } from "../lib/theme";
 import { api, type Me } from "../lib/api";
+import { LS, usePersistedState } from "../lib/storage";
 import Avatar from "./Avatar";
 import { notify, type NotifSettings } from "../lib/notifications";
 import Tooltip from "./Tooltip";
+import { Section, SettingRow, Switch } from "./ui/form";
+import { DraftSaveBar } from "./ui/DraftSaveBar";
 import { useConfirm } from "./ConfirmProvider";
 
 // The Settings page edits server-persisted preferences as a draft: changes apply locally
@@ -38,14 +41,6 @@ const TABS: { id: TabId; icon: typeof Monitor }[] = [
   { id: "account", icon: User },
 ];
 
-// Persist the active tab so a reload (F5) keeps the user where they were instead of
-// snapping back to "appearance".
-const SETTINGS_TAB_KEY = "siftlode.settingsTab";
-function loadSettingsTab(): TabId {
-  const v = localStorage.getItem(SETTINGS_TAB_KEY);
-  return TABS.some((tabItem) => tabItem.id === v) ? (v as TabId) : "appearance";
-}
-
 // Settings as a page (Design B): rendered in the main content area, not an overlay. It keeps
 // the frosted `.glass` surface so it still refracts the ambient backdrop. The page title is
 // shown by the Header; the tab rail stays as in-page sub-navigation.
@@ -59,11 +54,11 @@ export default function SettingsPanel({
   onOpenWizard: () => void;
 }) {
   const { t } = useTranslation();
-  const [tab, setTabState] = useState<TabId>(loadSettingsTab);
-  const setTab = (id: TabId) => {
-    setTabState(id);
-    localStorage.setItem(SETTINGS_TAB_KEY, id);
-  };
+  const [tabRaw, setTab] = usePersistedState(LS.settingsTab, "appearance");
+  // Clamp at render so a stale/removed tab id falls back to Appearance.
+  const tab: TabId = TABS.some((tabItem) => tabItem.id === tabRaw)
+    ? (tabRaw as TabId)
+    : "appearance";
 
   return (
     <div className="p-4 max-w-3xl w-full mx-auto">
@@ -110,87 +105,22 @@ export default function SettingsPanel({
 
 function PrefsSaveBar({ prefs }: { prefs: PrefsController }) {
   const { t } = useTranslation();
-  // Stay mounted while a transient "saved"/"error" message is fading, even after dirty clears.
-  if (!prefs.dirty && prefs.saveState === "idle") return null;
-  const saving = prefs.saveState === "saving";
   return (
-    <div className="flex items-center justify-between gap-3 border-t border-border/60 px-4 py-3 bg-card/40">
-      <span className="text-sm text-muted">
-        {prefs.saveState === "saved"
-          ? <span className="text-emerald-500 inline-flex items-center gap-1.5"><Check className="w-4 h-4" />{t("settings.save.saved")}</span>
-          : prefs.saveState === "error"
-            ? <span className="text-red-500">{t("settings.save.failed")}</span>
-            : t("settings.save.unsaved")}
-      </span>
-      <div className="flex items-center gap-2">
-        <button
-          onClick={prefs.discard}
-          disabled={saving || !prefs.dirty}
-          className="glass-card glass-hover flex items-center gap-1.5 px-3 py-1.5 rounded-lg text-sm disabled:opacity-40 transition"
-        >
-          <RotateCcw className="w-4 h-4" />
-          {t("settings.save.discard")}
-        </button>
-        <button
-          onClick={prefs.save}
-          disabled={saving || !prefs.dirty}
-          className="flex items-center gap-1.5 px-3 py-1.5 rounded-lg text-sm bg-accent text-accent-fg font-medium shadow-md shadow-accent/20 disabled:opacity-40 transition"
-        >
-          <Save className="w-4 h-4" />
-          {saving ? t("settings.save.saving") : t("settings.save.save")}
-        </button>
-      </div>
-    </div>
-  );
-}
-
-function Section({ title, children }: { title: string; children: React.ReactNode }) {
-  return (
-    <div className="mb-6">
-      <div className="text-xs uppercase tracking-wide text-muted mb-2">{title}</div>
-      {children}
-    </div>
-  );
-}
-
-function Row({
-  label,
-  hint,
-  children,
-}: {
-  label: string;
-  hint?: string;
-  children: React.ReactNode;
-}) {
-  return (
-    <div className="flex items-center justify-between gap-3 py-1.5 text-sm">
-      <Tooltip hint={hint ?? ""}>
-        <span
-          className={
-            hint ? "underline decoration-dotted decoration-muted/40 underline-offset-4 cursor-help" : ""
-          }
-        >
-          {label}
-        </span>
-      </Tooltip>
-      {children}
-    </div>
-  );
-}
-
-function Switch({ checked, onChange }: { checked: boolean; onChange: (v: boolean) => void }) {
-  return (
-    <button
-      type="button"
-      onClick={() => onChange(!checked)}
-      className={`w-9 h-5 rounded-full transition relative shrink-0 ${checked ? "bg-accent" : "bg-border"}`}
-    >
-      <span
-        className={`absolute top-0.5 w-4 h-4 rounded-full bg-white shadow transition-all ${
-          checked ? "left-[18px]" : "left-0.5"
-        }`}
-      />
-    </button>
+    <DraftSaveBar
+      variant="inline"
+      dirty={prefs.dirty}
+      state={prefs.saveState}
+      onSave={prefs.save}
+      onDiscard={prefs.discard}
+      labels={{
+        saved: t("settings.save.saved"),
+        failed: t("settings.save.failed"),
+        unsaved: t("settings.save.unsaved"),
+        discard: t("settings.save.discard"),
+        save: t("settings.save.save"),
+        saving: t("settings.save.saving"),
+      }}
+    />
   );
 }
 
@@ -219,27 +149,27 @@ function Appearance({ prefs }: { prefs: PrefsController }) {
       </Section>
 
       <Section title={t("settings.appearance.display")}>
-        <Row label={t("settings.appearance.darkMode")}>
+        <SettingRow label={t("settings.appearance.darkMode")}>
           <Switch
             checked={theme.mode === "dark"}
             onChange={(v) => setTheme({ ...theme, mode: v ? "dark" : "light" })}
           />
-        </Row>
-        <Row label={t("settings.appearance.listView")} hint={t("settings.appearance.listViewHint")}>
+        </SettingRow>
+        <SettingRow label={t("settings.appearance.listView")} hint={t("settings.appearance.listViewHint")}>
           <Switch checked={view === "list"} onChange={(v) => setView(v ? "list" : "grid")} />
-        </Row>
-        <Row
+        </SettingRow>
+        <SettingRow
           label={t("settings.appearance.performanceMode")}
           hint={t("settings.appearance.performanceModeHint")}
         >
           <Switch checked={perf} onChange={setPerf} />
-        </Row>
-        <Row
+        </SettingRow>
+        <SettingRow
           label={t("settings.appearance.showHints")}
           hint={t("settings.appearance.showHintsHint")}
         >
           <Switch checked={hints} onChange={setHints} />
-        </Row>
+        </SettingRow>
       </Section>
 
       <Section title={t("settings.appearance.textSize")}>
@@ -268,18 +198,18 @@ function Notifications({ prefs }: { prefs: PrefsController }) {
 
   return (
     <Section title={t("settings.notifications.title")}>
-      <Row
+      <SettingRow
         label={t("settings.notifications.sound")}
         hint={t("settings.notifications.soundHint")}
       >
         <Switch checked={cfg.sound} onChange={(v) => update({ sound: v })} />
-      </Row>
-      <Row
+      </SettingRow>
+      <SettingRow
         label={t("settings.notifications.autoDismiss")}
         hint={t("settings.notifications.autoDismissHint")}
       >
         <Switch checked={autoOn} onChange={(v) => update({ durationMs: v ? 6000 : 0 })} />
-      </Row>
+      </SettingRow>
       {autoOn && (
         <div className="py-1.5 text-sm">
           <div className="flex items-center justify-between">
diff --git a/frontend/src/components/Sidebar.tsx b/frontend/src/components/Sidebar.tsx
index df82d27..ecf64f0 100644
--- a/frontend/src/components/Sidebar.tsx
+++ b/frontend/src/components/Sidebar.tsx
@@ -36,6 +36,7 @@ import {
 } from "../lib/sidebarLayout";
 import { shareUrl } from "../lib/urlState";
 import { notify } from "../lib/notifications";
+import { Switch } from "./ui/form";
 import TagManager from "./TagManager";
 
 // Filter ids; display labels resolved at render time via t("sidebar.sort.<id>") etc.
@@ -622,19 +623,7 @@ function Toggle({
   return (
     <label className="flex items-center justify-between py-1 cursor-pointer text-sm">
       <span>{label}</span>
-      <button
-        type="button"
-        onClick={() => onChange(!checked)}
-        className={`w-9 h-5 rounded-full transition relative ${
-          checked ? "bg-accent" : "bg-border"
-        }`}
-      >
-        <span
-          className={`absolute top-0.5 w-4 h-4 rounded-full bg-white transition-all ${
-            checked ? "left-[18px]" : "left-0.5"
-          }`}
-        />
-      </button>
+      <Switch checked={checked} onChange={onChange} />
     </label>
   );
 }
diff --git a/frontend/src/components/Stats.tsx b/frontend/src/components/Stats.tsx
index 97a6109..f1b6db6 100644
--- a/frontend/src/components/Stats.tsx
+++ b/frontend/src/components/Stats.tsx
@@ -5,10 +5,11 @@ import { History, Pause, Play, RefreshCw } from "lucide-react";
 import { api, type AdminQuotaRow, type Me } from "../lib/api";
 import { formatEta, quotaActionLabel } from "../lib/format";
 import { notify } from "../lib/notifications";
+import { LS, usePersistedState } from "../lib/storage";
 import Tooltip from "./Tooltip";
+import { Section, SettingRow } from "./ui/form";
 
 const RANGES = [7, 30, 90] as const;
-const STATS_TAB_KEY = "siftlode.statsTab";
 type StatsTab = "overview" | "system";
 
 // Usage & stats page. "Overview" is per-user (sync status + your own API usage + actions);
@@ -17,14 +18,9 @@ type StatsTab = "overview" | "system";
 export default function Stats({ me }: { me: Me }) {
   const { t } = useTranslation();
   const isAdmin = me.role === "admin";
-  const [tab, setTabState] = useState<StatsTab>(() => {
-    const v = localStorage.getItem(STATS_TAB_KEY);
-    return v === "system" && isAdmin ? "system" : "overview";
-  });
-  const setTab = (id: StatsTab) => {
-    setTabState(id);
-    localStorage.setItem(STATS_TAB_KEY, id);
-  };
+  const [tabRaw, setTab] = usePersistedState(LS.statsTab, "overview");
+  // Clamp at render: only admins may land on the System tab (covers a stale stored value).
+  const tab: StatsTab = tabRaw === "system" && isAdmin ? "system" : "overview";
 
   return (
     <div className="p-4 max-w-4xl mx-auto">
@@ -52,31 +48,6 @@ export default function Stats({ me }: { me: Me }) {
   );
 }
 
-function Section({ title, children }: { title: string; children: React.ReactNode }) {
-  return (
-    <div className="mb-6">
-      <div className="text-xs uppercase tracking-wide text-muted mb-2">{title}</div>
-      {children}
-    </div>
-  );
-}
-
-function Row({ label, hint, children }: { label: string; hint?: string; children: React.ReactNode }) {
-  return (
-    <div className="flex items-center justify-between gap-3 py-1.5 text-sm">
-      <Tooltip hint={hint ?? ""}>
-        <span
-          className={
-            hint ? "underline decoration-dotted decoration-muted/40 underline-offset-4 cursor-help" : ""
-          }
-        >
-          {label}
-        </span>
-      </Tooltip>
-      {children}
-    </div>
-  );
-}
 
 // Per-user view: sync status + your own API usage + (for real accounts) the manual sync actions.
 function Overview({ me }: { me: Me }) {
@@ -112,29 +83,29 @@ function Overview({ me }: { me: Me }) {
       <Section title={t("stats.sync.myStatus")}>
         {s ? (
           <div className="space-y-1.5 text-sm">
-            <Row label={t("stats.sync.channels")} hint={t("stats.sync.channelsHint")}>
+            <SettingRow label={t("stats.sync.channels")} hint={t("stats.sync.channelsHint")}>
               {s.channels_total}
-            </Row>
-            <Row label={t("stats.sync.recentSynced")} hint={t("stats.sync.recentSyncedHint")}>
+            </SettingRow>
+            <SettingRow label={t("stats.sync.recentSynced")} hint={t("stats.sync.recentSyncedHint")}>
               {`${s.channels_recent_synced}/${s.channels_total}`}
-            </Row>
-            <Row label={t("stats.sync.fullHistory")} hint={t("stats.sync.fullHistoryHint")}>
+            </SettingRow>
+            <SettingRow label={t("stats.sync.fullHistory")} hint={t("stats.sync.fullHistoryHint")}>
               {`${s.channels_deep_done}/${s.channels_deep_requested}`}
-            </Row>
+            </SettingRow>
             {s.deep_pending_count > 0 && (
-              <Row
+              <SettingRow
                 label={t("stats.sync.fullHistoryEta")}
                 hint={t("stats.sync.fullHistoryEtaHint", { count: s.deep_pending_count })}
               >
                 {formatEta(s.deep_eta_seconds)}
-              </Row>
+              </SettingRow>
             )}
-            <Row label={t("stats.sync.myVideos")} hint={t("stats.sync.myVideosHint")}>
+            <SettingRow label={t("stats.sync.myVideos")} hint={t("stats.sync.myVideosHint")}>
               {s.my_videos.toLocaleString()}
-            </Row>
-            <Row label={t("stats.sync.quotaLeft")} hint={t("stats.sync.quotaLeftHint")}>
+            </SettingRow>
+            <SettingRow label={t("stats.sync.quotaLeft")} hint={t("stats.sync.quotaLeftHint")}>
               {s.quota_remaining_today.toLocaleString()}
-            </Row>
+            </SettingRow>
           </div>
         ) : (
           <div className="text-muted text-sm">{t("stats.sync.loading")}</div>
@@ -145,12 +116,12 @@ function Overview({ me }: { me: Me }) {
         {usage.data ? (
           <>
             <div className="space-y-1.5 text-sm">
-              <Row label={t("stats.sync.today")} hint={t("stats.sync.todayHint")}>
+              <SettingRow label={t("stats.sync.today")} hint={t("stats.sync.todayHint")}>
                 {usage.data.today.toLocaleString()}
-              </Row>
-              <Row label={t("stats.sync.last7d")}>{usage.data.last_7d.toLocaleString()}</Row>
-              <Row label={t("stats.sync.last30d")}>{usage.data.last_30d.toLocaleString()}</Row>
-              <Row label={t("stats.sync.allTime")}>{usage.data.all_time.toLocaleString()}</Row>
+              </SettingRow>
+              <SettingRow label={t("stats.sync.last7d")}>{usage.data.last_7d.toLocaleString()}</SettingRow>
+              <SettingRow label={t("stats.sync.last30d")}>{usage.data.last_30d.toLocaleString()}</SettingRow>
+              <SettingRow label={t("stats.sync.allTime")}>{usage.data.all_time.toLocaleString()}</SettingRow>
             </div>
             {Object.keys(usage.data.by_action).length > 0 && (
               <div className="mt-2 pt-2 border-t border-border space-y-1 text-xs text-muted">
diff --git a/frontend/src/components/Tabs.tsx b/frontend/src/components/Tabs.tsx
index 7871c3d..42b1387 100644
--- a/frontend/src/components/Tabs.tsx
+++ b/frontend/src/components/Tabs.tsx
@@ -1,4 +1,4 @@
-import { useState } from "react";
+import { usePersistedState } from "../lib/storage";
 
 // Reusable horizontal pill tab-rail for in-page sub-navigation (Configuration, Users & roles…).
 // The active tab is persisted to localStorage so a reload (F5) keeps the user where they were,
@@ -10,16 +10,9 @@ export interface TabDef {
   badge?: number; // optional count pill (e.g. pending requests); hidden when 0/undefined
 }
 
-/** Persisted active-tab state. Validation is deferred to the caller (it clamps to a valid id at
- * render) so this can be called before an async-loaded tab list is known, keeping hook order stable. */
-export function usePersistedTab(storageKey: string, fallback = ""): [string, (id: string) => void] {
-  const [tab, setTabState] = useState<string>(() => localStorage.getItem(storageKey) ?? fallback);
-  const setTab = (id: string) => {
-    setTabState(id);
-    localStorage.setItem(storageKey, id);
-  };
-  return [tab, setTab];
-}
+/** Persisted active-tab state — the canonical helper now lives in lib/storage as
+ * `usePersistedState`; re-exported here under its original name for existing call sites. */
+export const usePersistedTab = usePersistedState;
 
 export default function Tabs({
   tabs,
diff --git a/frontend/src/components/ui/DraftSaveBar.tsx b/frontend/src/components/ui/DraftSaveBar.tsx
new file mode 100644
index 0000000..5e629af
--- /dev/null
+++ b/frontend/src/components/ui/DraftSaveBar.tsx
@@ -0,0 +1,75 @@
+import { Check, RotateCcw, Save } from "lucide-react";
+
+// The Save / Discard bar shown while an edited draft has unsaved changes (Settings prefs,
+// admin Configuration). Two visual variants share one state machine + markup:
+//   - "inline":   a bar pinned to the bottom of a card (Settings panel)
+//   - "floating": a centered floating pill over the page (Configuration page)
+// Renders nothing while clean and idle; stays mounted through the fading saved/error message.
+
+export type SaveState = "idle" | "saving" | "saved" | "error";
+
+export interface DraftSaveBarLabels {
+  saved: string;
+  failed: string;
+  unsaved: string;
+  discard: string;
+  save: string;
+  saving: string;
+}
+
+export function DraftSaveBar({
+  dirty,
+  state,
+  onSave,
+  onDiscard,
+  labels,
+  variant = "inline",
+}: {
+  dirty: boolean;
+  state: SaveState;
+  onSave: () => void;
+  onDiscard: () => void;
+  labels: DraftSaveBarLabels;
+  variant?: "inline" | "floating";
+}) {
+  if (!dirty && state === "idle") return null;
+  const saving = state === "saving";
+  const wrap =
+    variant === "floating"
+      ? "fixed bottom-4 left-1/2 -translate-x-1/2 z-40 glass rounded-2xl shadow-lg flex items-center justify-between gap-4 px-4 py-3 w-[min(48rem,calc(100%-2rem))]"
+      : "flex items-center justify-between gap-3 border-t border-border/60 px-4 py-3 bg-card/40";
+  return (
+    <div className={wrap}>
+      <span className="text-sm text-muted">
+        {state === "saved" ? (
+          <span className="text-emerald-500 inline-flex items-center gap-1.5">
+            <Check className="w-4 h-4" />
+            {labels.saved}
+          </span>
+        ) : state === "error" ? (
+          <span className="text-red-500">{labels.failed}</span>
+        ) : (
+          labels.unsaved
+        )}
+      </span>
+      <div className="flex items-center gap-2">
+        <button
+          onClick={onDiscard}
+          disabled={saving || !dirty}
+          className="glass-card glass-hover flex items-center gap-1.5 px-3 py-1.5 rounded-lg text-sm disabled:opacity-40 transition"
+        >
+          <RotateCcw className="w-4 h-4" />
+          {labels.discard}
+        </button>
+        <button
+          onClick={onSave}
+          disabled={saving || !dirty}
+          className="flex items-center gap-1.5 px-3 py-1.5 rounded-lg text-sm bg-accent text-accent-fg font-medium shadow-md shadow-accent/20 disabled:opacity-40 transition"
+        >
+          <Save className="w-4 h-4" />
+          {saving ? labels.saving : labels.save}
+        </button>
+      </div>
+    </div>
+  );
+}
diff --git a/frontend/src/components/ui/form.tsx b/frontend/src/components/ui/form.tsx
new file mode 100644
index 0000000..c99fcd3
--- /dev/null
+++ b/frontend/src/components/ui/form.tsx
@@ -0,0 +1,85 @@
+import type { ReactNode } from "react";
+import Tooltip from "../Tooltip";
+
+// Shared form/settings primitives, factored out of the many panels that each re-declared
+// them (Settings, Config, Stats, admin pages, Setup wizard). Visual contract unchanged.
+
+/** Pill on/off switch — the bare control; compose it with your own label/row. */
+export function Switch({
+  checked,
+  onChange,
+}: {
+  checked: boolean;
+  onChange: (v: boolean) => void;
+}) {
+  return (
+    <button
+      type="button"
+      onClick={() => onChange(!checked)}
+      className={`w-9 h-5 rounded-full transition relative shrink-0 ${checked ? "bg-accent" : "bg-border"}`}
+    >
+      <span
+        className={`absolute top-0.5 w-4 h-4 rounded-full bg-white shadow transition-all ${
+          checked ? "left-[18px]" : "left-0.5"
+        }`}
+      />
+    </button>
+  );
+}
+
+/** A titled settings block. Default = a plain block with an uppercase caption; `card` wraps it
+ * in a glass card (the admin pages' style). */
+export function Section({
+  title,
+  card,
+  children,
+}: {
+  title: string;
+  card?: boolean;
+  children: ReactNode;
+}) {
+  return (
+    <div className={card ? "glass rounded-2xl p-4 mb-4" : "mb-6"}>
+      <div className={`text-xs uppercase tracking-wide text-muted ${card ? "mb-3" : "mb-2"}`}>
+        {title}
+      </div>
+      {children}
+    </div>
+  );
+}
+
+/** A label that reveals an explanatory caption on hover (dotted underline) when `hint` is set.
+ * No-op styling when there's no hint, so it's safe to use unconditionally. */
+export function HintLabel({ hint, children }: { hint?: string; children: ReactNode }) {
+  return (
+    <Tooltip hint={hint ?? ""}>
+      <span
+        className={
+          hint
+            ? "underline decoration-dotted decoration-muted/40 underline-offset-4 cursor-help"
+            : ""
+        }
+      >
+        {children}
+      </span>
+    </Tooltip>
+  );
+}
+
+/** A settings row: a (hint-able) label on the left, a control on the right. */
+export function SettingRow({
+  label,
+  hint,
+  children,
+}: {
+  label: string;
+  hint?: string;
+  children: ReactNode;
+}) {
+  return (
+    <div className="flex items-center justify-between gap-3 py-1.5 text-sm">
+      <HintLabel hint={hint}>{label}</HintLabel>
+      {children}
+    </div>
+  );
+}
diff --git a/frontend/src/i18n/index.ts b/frontend/src/i18n/index.ts
index 50397b6..6cb3abc 100644
--- a/frontend/src/i18n/index.ts
+++ b/frontend/src/i18n/index.ts
@@ -1,5 +1,6 @@
 import i18n from "i18next";
 import { initReactI18next } from "react-i18next";
+import { LS } from "../lib/storage";
 
 // Endonyms (shown as-is regardless of the active language — the convention for language pickers).
 export const LANGUAGES = [
@@ -9,7 +10,7 @@ export const LANGUAGES = [
 ] as const;
 export type LangCode = (typeof LANGUAGES)[number]["code"];
 const SUPPORTED = LANGUAGES.map((l) => l.code) as readonly string[];
-export const LANG_KEY = "siftlode.lang";
+export const LANG_KEY = LS.lang;
 
 // Auto-load every locale file (locales/<lang>/<area>.json) and merge each <area> under one
 // `translation` namespace, so components use t("area.key") and adding an area needs no wiring.
diff --git a/frontend/src/i18n/locales/de/notifications.json b/frontend/src/i18n/locales/de/notifications.json
index ec7f745..5c7fdb3 100644
--- a/frontend/src/i18n/locales/de/notifications.json
+++ b/frontend/src/i18n/locales/de/notifications.json
@@ -11,11 +11,5 @@
   "openInManager": "Kanalverwaltung",
   "openOnYouTube": "Auf YouTube öffnen",
   "unhidden": "Eingeblendet „{{title}}”",
-  "unwatched": "Als nicht angesehen markiert „{{title}}”",
-  "time": {
-    "justNow": "gerade eben",
-    "minutes": "vor {{count}} Min.",
-    "hours": "vor {{count}} Std.",
-    "days": "vor {{count}} T."
-  }
+  "unwatched": "Als nicht angesehen markiert „{{title}}”"
 }
diff --git a/frontend/src/i18n/locales/de/time.json b/frontend/src/i18n/locales/de/time.json
index 1f1424b..80a00f7 100644
--- a/frontend/src/i18n/locales/de/time.json
+++ b/frontend/src/i18n/locales/de/time.json
@@ -6,5 +6,14 @@
   "daysAgo": "vor {{count}} T.",
   "weeksAgo": "vor {{count}} Wo.",
   "monthsAgo": "vor {{count}} Mon.",
-  "yearsAgo": "vor {{count}} J."
+  "yearsAgo": "vor {{count}} J.",
+  "eta": {
+    "now": "jetzt",
+    "done": "fertig",
+    "lessThanHour": "< 1 Stunde",
+    "hours_one": "~{{count}} Stunde",
+    "hours_other": "~{{count}} Stunden",
+    "days_one": "~{{count}} Tag",
+    "days_other": "~{{count}} Tage"
+  }
 }
diff --git a/frontend/src/i18n/locales/en/notifications.json b/frontend/src/i18n/locales/en/notifications.json
index 08a23dd..6a59040 100644
--- a/frontend/src/i18n/locales/en/notifications.json
+++ b/frontend/src/i18n/locales/en/notifications.json
@@ -11,11 +11,5 @@
   "openInManager": "Channel manager",
   "openOnYouTube": "Open on YouTube",
   "unhidden": "Unhidden “{{title}}”",
-  "unwatched": "Unwatched “{{title}}”",
-  "time": {
-    "justNow": "just now",
-    "minutes": "{{count}}m ago",
-    "hours": "{{count}}h ago",
-    "days": "{{count}}d ago"
-  }
+  "unwatched": "Unwatched “{{title}}”"
 }
diff --git a/frontend/src/i18n/locales/en/time.json b/frontend/src/i18n/locales/en/time.json
index c08ee22..f6d16ee 100644
--- a/frontend/src/i18n/locales/en/time.json
+++ b/frontend/src/i18n/locales/en/time.json
@@ -6,5 +6,14 @@
   "daysAgo": "{{count}}d ago",
   "weeksAgo": "{{count}} wk ago",
   "monthsAgo": "{{count}} mo ago",
-  "yearsAgo": "{{count}} yr ago"
+  "yearsAgo": "{{count}} yr ago",
+  "eta": {
+    "now": "now",
+    "done": "done",
+    "lessThanHour": "< 1 hour",
+    "hours_one": "~{{count}} hour",
+    "hours_other": "~{{count}} hours",
+    "days_one": "~{{count}} day",
+    "days_other": "~{{count}} days"
+  }
 }
diff --git a/frontend/src/i18n/locales/hu/notifications.json b/frontend/src/i18n/locales/hu/notifications.json
index e305c4b..5c37dbf 100644
--- a/frontend/src/i18n/locales/hu/notifications.json
+++ b/frontend/src/i18n/locales/hu/notifications.json
@@ -11,11 +11,5 @@
   "openInManager": "Csatornakezelő",
   "openOnYouTube": "Megnyitás a YouTube-on",
   "unhidden": "Megjelenítve: „{{title}}”",
-  "unwatched": "Megtekintés visszavonva: „{{title}}”",
-  "time": {
-    "justNow": "az imént",
-    "minutes": "{{count}} perce",
-    "hours": "{{count}} órája",
-    "days": "{{count}} napja"
-  }
+  "unwatched": "Megtekintés visszavonva: „{{title}}”"
 }
diff --git a/frontend/src/i18n/locales/hu/time.json b/frontend/src/i18n/locales/hu/time.json
index f3413b9..71ce423 100644
--- a/frontend/src/i18n/locales/hu/time.json
+++ b/frontend/src/i18n/locales/hu/time.json
@@ -6,5 +6,14 @@
   "daysAgo": "{{count}} napja",
   "weeksAgo": "{{count}} hete",
   "monthsAgo": "{{count}} hónapja",
-  "yearsAgo": "{{count}} éve"
+  "yearsAgo": "{{count}} éve",
+  "eta": {
+    "now": "most",
+    "done": "kész",
+    "lessThanHour": "< 1 óra",
+    "hours_one": "~{{count}} óra",
+    "hours_other": "~{{count}} óra",
+    "days_one": "~{{count}} nap",
+    "days_other": "~{{count}} nap"
+  }
 }
diff --git a/frontend/src/lib/descriptionLinks.tsx b/frontend/src/lib/descriptionLinks.tsx
new file mode 100644
index 0000000..dfc25b4
--- /dev/null
+++ b/frontend/src/lib/descriptionLinks.tsx
@@ -0,0 +1,147 @@
+import type { ReactNode } from "react";
+import type { TFunction } from "i18next";
+
+// Turn a video description into clickable nodes:
+//  - bare timestamps (mm:ss / hh:mm:ss) → seek the inline player
+//  - a YouTube link to the *current* video → seek (to its t= if any)
+//  - a YouTube link to *another* video → load it in the inline player
+//  - emails → mailto:, hashtags → YouTube's hashtag page, other URLs → new tab
+// Pure logic (no React state), factored out of PlayerModal so it's testable on its own.
+const URL_RE = /(https?:\/\/[^\s<>]+)/g;
+// One pass over plain text for the three inline token kinds (email | hashtag | timestamp).
+const INLINE_RE =
+  /([A-Za-z0-9._%+-]+@[A-Za-z0-9-]+\.[A-Za-z0-9.-]+)|(#[\p{L}\p{N}_]+)|(\b(?:\d{1,2}:)?\d{1,2}:\d{2}\b)/gu;
+
+function tsToSeconds(ts: string): number {
+  const parts = ts.split(":").map((n) => parseInt(n, 10));
+  return parts.length === 3
+    ? parts[0] * 3600 + parts[1] * 60 + parts[2]
+    : parts[0] * 60 + parts[1];
+}
+
+// Parse a YouTube `t`/`start` param: "90", "90s", or "1h2m3s".
+function parseStart(t: string | null): number | null {
+  if (!t) return null;
+  if (/^\d+$/.test(t)) return parseInt(t, 10) || null;
+  const m = t.match(/^(?:(\d+)h)?(?:(\d+)m)?(?:(\d+)s)?$/);
+  if (!m) return null;
+  const total =
+    parseInt(m[1] || "0", 10) * 3600 +
+    parseInt(m[2] || "0", 10) * 60 +
+    parseInt(m[3] || "0", 10);
+  return total || null;
+}
+
+// Extract a video id (+ optional start) from a YouTube URL, else null.
+function parseYouTube(url: string): { id: string; start: number | null } | null {
+  let u: URL;
+  try {
+    u = new URL(url);
+  } catch {
+    return null;
+  }
+  const host = u.hostname.replace(/^www\./, "");
+  let id: string | null = null;
+  if (host === "youtu.be") {
+    id = u.pathname.slice(1) || null;
+  } else if (host === "youtube.com" || host === "m.youtube.com" || host === "music.youtube.com") {
+    if (u.pathname === "/watch") id = u.searchParams.get("v");
+    else {
+      const m = u.pathname.match(/^\/(?:shorts|embed|live)\/([^/?#]+)/);
+      if (m) id = m[1];
+    }
+  }
+  if (!id) return null;
+  return { id, start: parseStart(u.searchParams.get("t") || u.searchParams.get("start")) };
+}
+
+export function renderDescription(
+  text: string,
+  opts: {
+    currentId: string;
+    onSeek: (seconds: number) => void;
+    onLoadVideo: (id: string, start: number | null) => void;
+    t: TFunction;
+  }
+): ReactNode[] {
+  const { t } = opts;
+  const out: ReactNode[] = [];
+  let key = 0;
+  const linkCls = "text-accent hover:underline break-all";
+  // Tidy YouTube descriptions: drop trailing spaces and remove blank lines entirely
+  // (they're just noise in the popover), keeping single line breaks.
+  const clean = text.replace(/[ \t]+\n/g, "\n").replace(/\n{2,}/g, "\n").trim();
+  for (const chunk of clean.split(URL_RE)) {
+    if (/^https?:\/\//.test(chunk)) {
+      const href = chunk.replace(/[.,;:!?)\]]+$/, "");
+      const yt = parseYouTube(href);
+      if (yt) {
+        const sameVideo = yt.id === opts.currentId;
+        out.push(
+          <button
+            key={key++}
+            onClick={() =>
+              sameVideo ? opts.onSeek(yt.start ?? 0) : opts.onLoadVideo(yt.id, yt.start)
+            }
+            className={linkCls}
+            title={sameVideo ? t("player.jumpToTime") : t("player.playInApp")}
+          >
+            {href}
+          </button>
+        );
+      } else {
+        out.push(
+          <a key={key++} href={href} target="_blank" rel="noreferrer" className={linkCls}>
+            {href}
+          </a>
+        );
+      }
+      continue;
+    }
+    // Plain text: pull out emails, hashtags and bare timestamps.
+    INLINE_RE.lastIndex = 0;
+    let last = 0;
+    let m: RegExpExecArray | null;
+    while ((m = INLINE_RE.exec(chunk))) {
+      if (m.index > last) out.push(<span key={key++}>{chunk.slice(last, m.index)}</span>);
+      if (m[1]) {
+        // Email — trim trailing punctuation the domain rule may have swallowed.
+        const email = m[1].replace(/[.,;:]+$/, "");
+        out.push(
+          <a key={key++} href={`mailto:${email}`} className={linkCls}>
+            {email}
+          </a>
+        );
+        if (m[1].length > email.length) out.push(<span key={key++}>{m[1].slice(email.length)}</span>);
+      } else if (m[2]) {
+        // Hashtag → YouTube's hashtag feed (mirrors native YouTube behavior).
+        const tag = m[2].slice(1);
+        out.push(
+          <a
+            key={key++}
+            href={`https://www.youtube.com/hashtag/${encodeURIComponent(tag)}`}
+            target="_blank"
+            rel="noreferrer"
+            className={linkCls}
+          >
+            {m[2]}
+          </a>
+        );
+      } else {
+        const ts = m[3];
+        out.push(
+          <button
+            key={key++}
+            onClick={() => opts.onSeek(tsToSeconds(ts))}
+            className="text-accent hover:underline"
+          >
+            {ts}
+          </button>
+        );
+      }
+      last = m.index + m[0].length;
+    }
+    if (last < chunk.length) out.push(<span key={key++}>{chunk.slice(last)}</span>);
+  }
+  return out;
+}
diff --git a/frontend/src/lib/errorDialog.ts b/frontend/src/lib/errorDialog.ts
index 63c3c66..70f5a4c 100644
--- a/frontend/src/lib/errorDialog.ts
+++ b/frontend/src/lib/errorDialog.ts
@@ -1,4 +1,5 @@
 import i18n from "../i18n";
+import { createStore } from "./store";
 
 // A single, self-explanatory error dialog (modal) the user must acknowledge — used when the
 // server can't carry out an action (a definitive 4xx/5xx response). Distinct from toasts
@@ -9,30 +10,18 @@ export interface AppError {
   message: string;
 }
 
-let current: AppError | null = null;
-let listeners: Array<() => void> = [];
-const emit = () => listeners.forEach((l) => l());
+const store = createStore<AppError | null>(null);
 
 export function reportError(message?: string, title?: string): void {
-  current = {
+  store.set({
     title: title || i18n.t("errors.title"),
     message: message || i18n.t("errors.generic"),
-  };
-  emit();
+  });
 }
 
 export function dismissError(): void {
-  current = null;
-  emit();
+  store.set(null);
 }
 
-export function subscribeError(listener: () => void): () => void {
-  listeners.push(listener);
-  return () => {
-    listeners = listeners.filter((l) => l !== listener);
-  };
-}
-
-export function getError(): AppError | null {
-  return current;
-}
+export const subscribeError = store.subscribe;
+export const getError = store.get;
diff --git a/frontend/src/lib/format.ts b/frontend/src/lib/format.ts
index d7ebe17..e0bb0d4 100644
--- a/frontend/src/lib/format.ts
+++ b/frontend/src/lib/format.ts
@@ -2,8 +2,14 @@ import i18n from "../i18n";
 
 export function relativeTime(iso: string | null): string {
   if (!iso) return "";
-  const then = new Date(iso).getTime();
-  const secs = Math.max(0, (Date.now() - then) / 1000);
+  return relativeFromMs(new Date(iso).getTime());
+}
+
+/** Relative-time label from an epoch-millis timestamp (the ms-based half of relativeTime, for
+ * client-side notifications whose timestamps are already numbers). One implementation, one
+ * set of `time.*` strings — shared instead of re-implemented per component. */
+export function relativeFromMs(ms: number): string {
+  const secs = Math.max(0, (Date.now() - ms) / 1000);
   const units: [number, string][] = [
     [60, "time.secondsAgo"],
     [3600, "time.minutesAgo"],
@@ -51,17 +57,21 @@ export function quotaActionLabel(action: string): string {
   return i18n.t(`quotaActions.${action}`, { defaultValue: action });
 }
 
-/** Coarse, human ETA for a remaining duration in seconds ("~3 hours", "~2 days"). */
+/** Coarse, human ETA for a remaining duration in seconds ("~3 hours", "~2 days"). Translated
+ * via the `time.eta.*` keys (was hardcoded English, violating the trilingual rule). */
 export function formatEta(seconds: number): string {
-  if (seconds <= 0) return "done";
+  if (seconds <= 0) return i18n.t("time.eta.done");
   const hours = seconds / 3600;
-  if (hours < 1) return "< 1 hour";
-  if (hours < 24) {
-    const h = Math.round(hours);
-    return `~${h} hour${h === 1 ? "" : "s"}`;
-  }
-  const d = Math.round(hours / 24);
-  return `~${d} day${d === 1 ? "" : "s"}`;
+  if (hours < 1) return i18n.t("time.eta.lessThanHour");
+  if (hours < 24) return i18n.t("time.eta.hours", { count: Math.round(hours) });
+  return i18n.t("time.eta.days", { count: Math.round(hours / 24) });
+}
+
+/** Compact whole-channel total length ("12 h", "45 m"), hours-scale so H:MM:SS isn't huge. */
+export function formatTotalHours(sec: number): string {
+  if (!sec) return "—";
+  const h = Math.round(sec / 3600);
+  return h >= 1 ? `${h.toLocaleString()} h` : `${Math.max(1, Math.round(sec / 60))} m`;
 }
 
 export function formatViews(n: number | null): string {
diff --git a/frontend/src/lib/hints.ts b/frontend/src/lib/hints.ts
index cb3b274..b4ecaae 100644
--- a/frontend/src/lib/hints.ts
+++ b/frontend/src/lib/hints.ts
@@ -1,36 +1,27 @@
 // App-wide "hints" toggle: when on, Tooltip components reveal short explanatory
 // captions on hover so the UI is somewhat self-documenting for new users. Experienced
 // users can turn it off in Settings. Persisted to localStorage (+ server preferences).
-const KEY = "siftlode.hints";
-
-let enabled = load();
-let listeners: Array<() => void> = [];
+import { createStore } from "./store";
+import { LS } from "./storage";
 
 function load(): boolean {
   try {
-    return localStorage.getItem(KEY) !== "0"; // default ON
+    return localStorage.getItem(LS.hints) !== "0"; // default ON
   } catch {
     return true;
   }
 }
 
-export function hintsEnabled(): boolean {
-  return enabled;
-}
+const store = createStore<boolean>(load());
+
+export const hintsEnabled = store.get;
+export const subscribeHints = store.subscribe;
 
 export function setHintsEnabled(v: boolean): void {
-  enabled = v;
+  store.set(v);
   try {
-    localStorage.setItem(KEY, v ? "1" : "0");
+    localStorage.setItem(LS.hints, v ? "1" : "0");
   } catch {
     /* ignore */
   }
-  listeners.forEach((l) => l());
-}
-
-export function subscribeHints(listener: () => void): () => void {
-  listeners.push(listener);
-  return () => {
-    listeners = listeners.filter((l) => l !== listener);
-  };
 }
diff --git a/frontend/src/lib/notifications.ts b/frontend/src/lib/notifications.ts
index 9e6ff0c..80aa84b 100644
--- a/frontend/src/lib/notifications.ts
+++ b/frontend/src/lib/notifications.ts
@@ -2,6 +2,7 @@
 // the Notification Center shows (info events, actions awaiting interaction, and app
 // errors). History is persisted to localStorage so it survives reloads; action
 // callbacks are live-only and dropped on reload.
+import { LS, readJSON, readMerged, writeJSON } from "./storage";
 
 export type NotifLevel = "info" | "success" | "warning" | "error" | "fatal";
 
@@ -71,8 +72,8 @@ export interface NotifyInput {
   transient?: boolean; // live status: sticky toast, not persisted (see Notification.transient)
 }
 
-const HISTORY_KEY = "siftlode.notifications";
-const SETTINGS_KEY = "siftlode.notifSettings";
+const HISTORY_KEY = LS.notifHistory;
+const SETTINGS_KEY = LS.notifSettings;
 const MAX_HISTORY = 100;
 const ERROR_TTL = 15000;
 
@@ -86,11 +87,7 @@ const DEFAULT_SETTINGS: NotifSettings = { sound: false, durationMs: 6000 };
 let config: NotifSettings = loadSettings();
 
 function loadSettings(): NotifSettings {
-  try {
-    return { ...DEFAULT_SETTINGS, ...JSON.parse(localStorage.getItem(SETTINGS_KEY) || "{}") };
-  } catch {
-    return DEFAULT_SETTINGS;
-  }
+  return readMerged(SETTINGS_KEY, DEFAULT_SETTINGS);
 }
 
 export function getNotifSettings(): NotifSettings {
@@ -99,11 +96,7 @@ export function getNotifSettings(): NotifSettings {
 
 export function configureNotifications(p: Partial<NotifSettings>): void {
   config = { ...config, ...p };
-  try {
-    localStorage.setItem(SETTINGS_KEY, JSON.stringify(config));
-  } catch {
-    /* ignore */
-  }
+  writeJSON(SETTINGS_KEY, config);
 }
 
 let audioCtx: AudioContext | null = null;
@@ -137,7 +130,7 @@ let cachedUnread = 0;
 
 function load(): Notification[] {
   try {
-    const raw = JSON.parse(localStorage.getItem(HISTORY_KEY) || "[]");
+    const raw = readJSON<unknown>(HISTORY_KEY, []);
     if (!Array.isArray(raw)) return [];
     // Restored entries are history only. Mark them dismissed so they don't
     // resurrect as active toasts on reload — their auto-dismiss timers aren't
@@ -154,7 +147,7 @@ function persist() {
     // Transient status notices are live-session only — never write them to history,
     // so a reload can't leave one stranded with no producer left to clear it.
     const slim = items.filter((n) => !n.transient).map(({ action: _action, ...n }) => n);
-    localStorage.setItem(HISTORY_KEY, JSON.stringify(slim));
+    writeJSON(HISTORY_KEY, slim);
   } catch {
     /* ignore quota / serialization errors */
   }
diff --git a/frontend/src/lib/onboarding.ts b/frontend/src/lib/onboarding.ts
index 496e915..26822c3 100644
--- a/frontend/src/lib/onboarding.ts
+++ b/frontend/src/lib/onboarding.ts
@@ -12,8 +12,10 @@
 //                                       suppresses the auto-popup on future logins (they
 //                                       can still reopen it from Settings → Account).
 
-export const ONBOARD_ACTIVE = "siftlode.onboarding.active";
-export const ONBOARD_DISMISSED = "siftlode.onboarding.dismissed";
+import { LS } from "./storage";
+
+export const ONBOARD_ACTIVE = "siftlode.onboarding.active"; // sessionStorage (not in LS, which is localStorage)
+export const ONBOARD_DISMISSED = LS.onboardingDismissed;
 
 export function shouldAutoOpenOnboarding(me: {
   can_read: boolean;
diff --git a/frontend/src/lib/releaseNotes.ts b/frontend/src/lib/releaseNotes.ts
index 2809643..fe84933 100644
--- a/frontend/src/lib/releaseNotes.ts
+++ b/frontend/src/lib/releaseNotes.ts
@@ -14,6 +14,19 @@ export interface ReleaseEntry {
 }
 
 export const RELEASE_NOTES: ReleaseEntry[] = [
+  {
+    version: "0.17.0",
+    date: "2026-06-29",
+    summary: "Messaging and notification fixes, plus a large under-the-hood cleanup.",
+    fixes: [
+      "Switching between signed-in accounts no longer drops you on a blank chat: after you switch, a message you just received shows up in the right conversation instead of an empty screen.",
+      "You're now reliably notified when a video you'd saved or added to a playlist is removed because it's no longer available on YouTube — this notice could previously be missed.",
+      "“Time remaining” estimates (e.g. on sync progress) and a few small labels are now translated in Hungarian and German like the rest of the app.",
+    ],
+    chores: [
+      "A large internal code cleanup: removed duplicated logic across the backend and frontend and factored out shared building blocks (form controls, the save/discard bar, popovers, browser-storage helpers, time/date formatters). No change to how the app behaves — groundwork that keeps future features consistent and quicker to build.",
+    ],
+  },
   {
     version: "0.16.2",
     date: "2026-06-26",
diff --git a/frontend/src/lib/sidebarLayout.ts b/frontend/src/lib/sidebarLayout.ts
index fe98f9c..0b7508f 100644
--- a/frontend/src/lib/sidebarLayout.ts
+++ b/frontend/src/lib/sidebarLayout.ts
@@ -4,6 +4,8 @@
 
 // `show`, `sort` and `content` moved to the feed toolbar (above the cards); they are no
 // longer sidebar widgets. normalizeLayout drops them from any persisted layout automatically.
+import { LS, readJSON, writeJSON } from "./storage";
+
 export type WidgetId = "date" | "language" | "topic" | "tags";
 
 export const ALL_WIDGETS: WidgetId[] = ["date", "language", "topic", "tags"];
@@ -27,8 +29,6 @@ export const DEFAULT_LAYOUT: SidebarLayout = {
   hidden: {},
 };
 
-const KEY = "siftlode.sidebarLayout";
-
 // Tolerate stale/partial data: keep only known widgets and append any that are missing
 // (e.g. a widget added in a later version) so nothing silently disappears.
 export function normalizeLayout(raw: unknown): SidebarLayout {
@@ -45,13 +45,9 @@ export function normalizeLayout(raw: unknown): SidebarLayout {
 }
 
 export function loadLayout(): SidebarLayout {
-  try {
-    return normalizeLayout(JSON.parse(localStorage.getItem(KEY) || "{}"));
-  } catch {
-    return DEFAULT_LAYOUT;
-  }
+  return normalizeLayout(readJSON<unknown>(LS.sidebarLayout, {}));
 }
 
 export function saveLayoutLocal(l: SidebarLayout): void {
-  localStorage.setItem(KEY, JSON.stringify(l));
+  writeJSON(LS.sidebarLayout, l);
 }
diff --git a/frontend/src/lib/storage.ts b/frontend/src/lib/storage.ts
new file mode 100644
index 0000000..80648d4
--- /dev/null
+++ b/frontend/src/lib/storage.ts
@@ -0,0 +1,80 @@
+import { useState } from "react";
+
+// Central registry of every localStorage key the app uses. One place to see them all, rename
+// safely, and avoid collisions — instead of `"siftlode.x"` string literals scattered across
+// files. Parametric (per-user) keys are functions. All keys are namespaced `siftlode.*`.
+export const LS = {
+  theme: "siftlode.theme",
+  sidebarLayout: "siftlode.sidebarLayout",
+  hints: "siftlode.hints",
+  lang: "siftlode.lang",
+  filters: "siftlode.filters",
+  page: "siftlode.page",
+  perfMode: "siftlode.perfMode",
+  channelFilter: "siftlode.channelFilter",
+  channelsView: "siftlode.channelsView",
+  settingsTab: "siftlode.settingsTab",
+  statsTab: "siftlode.statsTab",
+  adminUsersTab: "siftlode.adminUsersTab",
+  navCollapsed: "siftlode.navCollapsed",
+  playlist: "siftlode.playlist",
+  plSort: "siftlode.plSort",
+  notifHistory: "siftlode.notifications",
+  notifSettings: "siftlode.notifSettings",
+  onboardingDismissed: "siftlode.onboarding.dismissed",
+  seenVersion: "siftlode.seenVersion",
+  chatDock: (userId: number) => `siftlode.chatDock.${userId}`,
+} as const;
+
+// --- typed read/write helpers (do the JSON + try/catch once) ----------------------------
+
+/** Read an object-shaped value merged over `defaults` (so missing/added keys are tolerated),
+ * falling back to `defaults` on missing or corrupt data. */
+export function readMerged<T extends object>(key: string, defaults: T): T {
+  try {
+    return { ...defaults, ...JSON.parse(localStorage.getItem(key) || "{}") };
+  } catch {
+    return { ...defaults };
+  }
+}
+
+/** Read any JSON value (arrays/scalars), falling back on missing or corrupt data. */
+export function readJSON<T>(key: string, fallback: T): T {
+  try {
+    const raw = localStorage.getItem(key);
+    return raw == null ? fallback : (JSON.parse(raw) as T);
+  } catch {
+    return fallback;
+  }
+}
+
+/** Persist a value as JSON, swallowing quota/serialization errors. */
+export function writeJSON(key: string, value: unknown): void {
+  try {
+    localStorage.setItem(key, JSON.stringify(value));
+  } catch {
+    /* ignore quota / serialization errors */
+  }
+}
+
+// --- reactive persisted string state ----------------------------------------------------
+
+/** A `useState` whose string value is mirrored to localStorage, so it survives a reload (F5).
+ * Validation is deferred to the caller (clamp at render) so it can be used before an
+ * async-loaded option list is known, keeping hook order stable. Generalizes the per-component
+ * "persisted active tab" pattern (Settings, Stats, admin pages, the channel filter…). */
+export function usePersistedState(
+  key: string,
+  fallback = "",
+): [string, (value: string) => void] {
+  const [value, setValue] = useState<string>(() => localStorage.getItem(key) ?? fallback);
+  const set = (next: string) => {
+    setValue(next);
+    try {
+      localStorage.setItem(key, next);
+    } catch {
+      /* ignore */
+    }
+  };
+  return [value, set];
+}
diff --git a/frontend/src/lib/store.ts b/frontend/src/lib/store.ts
new file mode 100644
index 0000000..8f68e9a
--- /dev/null
+++ b/frontend/src/lib/store.ts
@@ -0,0 +1,33 @@
+import { useSyncExternalStore } from "react";
+
+// A minimal observable value shared across React components AND non-React code (the api
+// layer, websocket handlers, etc.). Replaces the hand-rolled `listeners`/`subscribe`/`emit`
+// triad that several modules each re-implemented slightly differently.
+export interface Store<T> {
+  get(): T;
+  set(next: T | ((prev: T) => T)): void;
+  subscribe(listener: () => void): () => void;
+  /** Subscribe from a component; re-renders on every change. */
+  use(): T;
+}
+
+export function createStore<T>(initial: T): Store<T> {
+  let value = initial;
+  const listeners = new Set<() => void>();
+  const get = () => value;
+  const subscribe = (l: () => void) => {
+    listeners.add(l);
+    return () => {
+      listeners.delete(l);
+    };
+  };
+  return {
+    get,
+    set(next) {
+      value = typeof next === "function" ? (next as (p: T) => T)(value) : next;
+      listeners.forEach((l) => l());
+    },
+    subscribe,
+    use: () => useSyncExternalStore(subscribe, get, get),
+  };
+}
diff --git a/frontend/src/lib/theme.ts b/frontend/src/lib/theme.ts
index ccfdfca..e841652 100644
--- a/frontend/src/lib/theme.ts
+++ b/frontend/src/lib/theme.ts
@@ -1,3 +1,5 @@
+import { LS, readMerged, writeJSON } from "./storage";
+
 export type Mode = "dark" | "light";
 export type Scheme = "midnight" | "forest" | "slate" | "youtube";
 
@@ -27,16 +29,10 @@ export function applyTheme(t: ThemePrefs): void {
   el.style.setProperty("--font-scale", String(t.fontScale));
 }
 
-const KEY = "siftlode.theme";
-
 export function loadLocalTheme(): ThemePrefs {
-  try {
-    return { ...DEFAULT_THEME, ...JSON.parse(localStorage.getItem(KEY) || "{}") };
-  } catch {
-    return DEFAULT_THEME;
-  }
+  return readMerged(LS.theme, DEFAULT_THEME);
 }
 
 export function saveLocalTheme(t: ThemePrefs): void {
-  localStorage.setItem(KEY, JSON.stringify(t));
+  writeJSON(LS.theme, t);
 }
diff --git a/frontend/src/lib/useDismiss.ts b/frontend/src/lib/useDismiss.ts
new file mode 100644
index 0000000..58c7fbe
--- /dev/null
+++ b/frontend/src/lib/useDismiss.ts
@@ -0,0 +1,32 @@
+import { useEffect, type RefObject } from "react";
+
+/** While `active`, close (call `onClose`) on Escape or a mousedown outside ALL of the given
+ * element(s). The reusable half of the popover/dropdown pattern that several components each
+ * hand-rolled; positioning stays with the caller (it varies per popover). Pass the panel ref
+ * (and optionally a trigger ref so clicking the trigger doesn't immediately re-close). */
+export function useDismiss(
+  active: boolean,
+  onClose: () => void,
+  refs: RefObject<HTMLElement | null> | RefObject<HTMLElement | null>[],
+): void {
+  useEffect(() => {
+    if (!active) return;
+    const list = Array.isArray(refs) ? refs : [refs];
+    const onDown = (e: MouseEvent) => {
+      const target = e.target as Node;
+      if (!list.some((r) => r.current?.contains(target))) onClose();
+    };
+    const onKey = (e: KeyboardEvent) => {
+      if (e.key === "Escape") onClose();
+    };
+    document.addEventListener("mousedown", onDown);
+    document.addEventListener("keydown", onKey);
+    return () => {
+      document.removeEventListener("mousedown", onDown);
+      document.removeEventListener("keydown", onKey);
+    };
+    // Matches the original effects: (re)subscribe only when open/closed toggles. Refs are
+    // stable and onClose is read fresh from this run's closure.
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [active]);
+}
diff --git a/frontend/src/lib/version.ts b/frontend/src/lib/version.ts
index caa07a4..e7ee557 100644
--- a/frontend/src/lib/version.ts
+++ b/frontend/src/lib/version.ts
@@ -1,8 +1,10 @@
 // Build info baked into the SPA at build time (Vite inlines VITE_*-prefixed env).
 // Injected via Docker build-args (see Dockerfile); falls back to "dev" for un-stamped builds.
+import { LS } from "./storage";
+
 export const FRONTEND_VERSION = import.meta.env.VITE_APP_VERSION || "dev";
 export const FRONTEND_SHA = import.meta.env.VITE_GIT_SHA || "unknown";
 export const FRONTEND_BUILD_DATE = import.meta.env.VITE_BUILD_DATE || "";
 
 // Key for the "last version the user has seen release notes for" (drives the banner).
-export const SEEN_VERSION_KEY = "siftlode.seenVersion";
+export const SEEN_VERSION_KEY = LS.seenVersion;