refactor(quota): canonical <entity>_<action> taxonomy for quota events

The quota-attribution action keys were inconsistent (mixed verbs, ad-hoc names,
English-only labels). Introduce a QuotaAction constants holder (one source of
truth), rename every attribution call site to it, and add migration 0020 to
rename historical quota_events.action values. The display label now resolves
from i18n (quotaActions.<key>, EN/HU/DE) instead of a hard-coded English map.
Scheduler job ids and progress phase labels are a separate namespace and are
left untouched.

backend/alembic/versions/0020_rename_quota_actions.py

@@ -0,0 +1,51 @@
+"""rename quota_events.action to the canonical <entity>_<action> taxonomy
+
+Revision ID: 0020_rename_quota_actions
+Revises: 0019_user_yt_channel_id
+Create Date: 2026-06-19
+
+The quota-attribution action keys were inconsistent (mixed verbs, ad-hoc names). Rename the
+stored historical values to the canonical scheme defined in app.quota.QuotaAction:
+``<entity>_<action>``, snake_case, explicit pull/push. Pure data migration on quota_events;
+fully reversible. (Scheduler job ids and progress phase labels are a separate namespace and
+are NOT touched.)
+"""
+from typing import Sequence, Union
+
+import sqlalchemy as sa
+from alembic import op
+
+revision: str = "0020_rename_quota_actions"
+down_revision: Union[str, None] = "0019_user_yt_channel_id"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+# old action value -> new canonical key (mirrors app.quota.QuotaAction).
+RENAMES: list[tuple[str, str]] = [
+    ("sync_subscriptions", "subscriptions_pull"),
+    ("subscription_resync", "subscriptions_resync"),
+    ("playlist_sync", "playlists_pull"),
+    ("playlist_push", "playlists_push"),
+    ("playlist_delete", "playlists_delete"),
+    ("backfill_recent", "videos_backfill_recent"),
+    ("backfill_deep", "videos_backfill_full"),
+    ("enrich", "videos_enrich"),
+    ("video_lookup", "videos_lookup"),
+    ("discovery", "channels_discover"),
+    ("subscribe", "channels_subscribe"),
+    ("unsubscribe", "channels_unsubscribe"),
+    ("maintenance", "maintenance_revalidate"),
+    ("api", "other"),
+]
+
+_SQL = sa.text("UPDATE quota_events SET action = :to WHERE action = :frm")
+
+
+def upgrade() -> None:
+    for frm, to in RENAMES:
+        op.execute(_SQL.bindparams(frm=frm, to=to))
+
+
+def downgrade() -> None:
+    for frm, to in RENAMES:
+        op.execute(_SQL.bindparams(frm=to, to=frm))

backend/app/quota.py

@@ -17,6 +17,32 @@ from app.models import ApiQuotaUsage, QuotaEvent
 
 _PACIFIC = ZoneInfo("America/Los_Angeles")
 
+
+class QuotaAction:
+    """Canonical quota-attribution action keys (one source of truth).
+
+    Naming scheme: ``<entity>_<action>``, all snake_case, explicit pull/push direction.
+    The stored value is this machine key; the user-facing label is resolved from i18n
+    (frontend ``quotaActions.<key>``). Distinct from scheduler job ids and progress phase
+    labels — do not conflate.
+    """
+
+    SUBSCRIPTIONS_PULL = "subscriptions_pull"
+    SUBSCRIPTIONS_RESYNC = "subscriptions_resync"
+    PLAYLISTS_PULL = "playlists_pull"
+    PLAYLISTS_PUSH = "playlists_push"
+    PLAYLISTS_DELETE = "playlists_delete"
+    VIDEOS_BACKFILL_RECENT = "videos_backfill_recent"
+    VIDEOS_BACKFILL_FULL = "videos_backfill_full"
+    VIDEOS_ENRICH = "videos_enrich"
+    VIDEOS_LOOKUP = "videos_lookup"
+    CHANNELS_DISCOVER = "channels_discover"
+    CHANNELS_SUBSCRIBE = "channels_subscribe"
+    CHANNELS_UNSUBSCRIBE = "channels_unsubscribe"
+    MAINTENANCE_REVALIDATE = "maintenance_revalidate"
+    OTHER = "other"
+
+
 # Request/job-scoped attribution for quota spend: who triggered it and what kind of work.
 # Set at entry points (route handlers, scheduler jobs) via attribute(); read by
 # record_usage. Default = background/system, generic action.
@@ -24,7 +50,7 @@ _actor_id: contextvars.ContextVar[int | None] = contextvars.ContextVar(
     "quota_actor_id", default=None
 )
 _action: contextvars.ContextVar[str] = contextvars.ContextVar(
-    "quota_action", default="api"
+    "quota_action", default=QuotaAction.OTHER
 )
 
 

backend/app/routes/channels.py

@@ -166,7 +166,7 @@ def discover_channels(
     # to yourself. Lazy + cached; needs OAuth, so demo / token-less users just skip it.
     if user.yt_channel_id is None and user.token is not None and not user.is_demo:
         try:
-            with quota.attribute(user.id, "discovery"), YouTubeClient(db, user) as yt:
+            with quota.attribute(user.id, quota.QuotaAction.CHANNELS_DISCOVER), YouTubeClient(db, user) as yt:
                 own = yt.get_my_channel_id()
             if own:
                 user.yt_channel_id = own
@@ -181,7 +181,7 @@ def discover_channels(
     need = [ch.id for ch, _, _ in rows if ch.details_synced_at is None][:DISCOVERY_ENRICH_CAP]
     if need:
         try:
-            with quota.attribute(user.id, "discovery"), YouTubeClient(db, user) as yt:
+            with quota.attribute(user.id, quota.QuotaAction.CHANNELS_DISCOVER), YouTubeClient(db, user) as yt:
                 apply_channel_details(db, yt.get_channels(need))
             db.commit()
             rows = _discovery_rows(db, user)
@@ -243,7 +243,7 @@ def update_channel(
     # fetched its recent uploads yet, do that one channel now (cheap) instead of waiting for
     # the scheduler. Deep paging still follows on the scheduler's next run (recent-then-deep).
     if deep_turned_on and channel is not None and channel.recent_synced_at is None:
-        with quota.attribute(user.id, "backfill_recent"):
+        with quota.attribute(user.id, quota.QuotaAction.VIDEOS_BACKFILL_RECENT):
             run_recent_backfill(db, [channel], max_channels=1)
 
     return {
@@ -274,7 +274,7 @@ def reset_backfill(
     channel.recent_synced_at = None
     sub.deep_requested = True
     db.commit()
-    with quota.attribute(user.id, "backfill_recent"):
+    with quota.attribute(user.id, quota.QuotaAction.VIDEOS_BACKFILL_RECENT):
         run_recent_backfill(db, [channel], max_channels=1)
     return {"id": channel_id, "reset": True}
 
@@ -306,7 +306,7 @@ def subscribe(
     if existing is not None:
         raise HTTPException(status_code=409, detail="Already subscribed to this channel.")
     try:
-        with quota.attribute(user.id, "subscribe"), YouTubeClient(db, user) as yt:
+        with quota.attribute(user.id, quota.QuotaAction.CHANNELS_SUBSCRIBE), YouTubeClient(db, user) as yt:
             yt_sub_id = yt.insert_subscription(channel_id)
             # Enrich a stub channel (title/thumbnail/subscriber count) so it shows up
             # properly right away; no video pull here.
@@ -356,7 +356,7 @@ def unsubscribe(
             detail="No YouTube subscription id on record — sync subscriptions first.",
         )
     try:
-        with quota.attribute(user.id, "unsubscribe"), YouTubeClient(db, user) as yt:
+        with quota.attribute(user.id, quota.QuotaAction.CHANNELS_UNSUBSCRIBE), YouTubeClient(db, user) as yt:
             yt.delete_subscription(sub.yt_subscription_id)
     except YouTubeError as exc:
         # 422 (a real, explainable error → speaking modal), not 502 which the client treats as

backend/app/routes/feed.py

@@ -549,7 +549,7 @@ def get_video_detail(
         }
 
     try:
-        with quota.attribute(user.id, "video_lookup"), YouTubeClient(db, user) as yt:
+        with quota.attribute(user.id, quota.QuotaAction.VIDEOS_LOOKUP), YouTubeClient(db, user) as yt:
             items = yt.get_videos([video_id])
     except YouTubeError as exc:
         raise HTTPException(status_code=422, detail=f"YouTube lookup failed: {exc}")

backend/app/routes/playlists.py

@@ -245,7 +245,7 @@ def sync_youtube(
             status_code=403,
             detail="Connect YouTube (read access) to sync your playlists.",
         )
-    with quota.attribute(user.id, "playlist_sync"):
+    with quota.attribute(user.id, quota.QuotaAction.PLAYLISTS_PULL):
         return sync_user_playlists(db, user)
 
 
@@ -266,7 +266,7 @@ def revert_youtube(
             status_code=403, detail="Connect YouTube (read access) to sync your playlists."
         )
     try:
-        with quota.attribute(user.id, "playlist_sync"):
+        with quota.attribute(user.id, quota.QuotaAction.PLAYLISTS_PULL):
             return repull_playlist(db, user, pl)
     except YouTubeError:
         db.rollback()
@@ -298,7 +298,7 @@ def push_plan(
             status_code=403, detail="Enable YouTube editing in Settings first."
         )
     try:
-        with quota.attribute(user.id, "playlist_push"):
+        with quota.attribute(user.id, quota.QuotaAction.PLAYLISTS_PUSH):
             plan = plan_push(db, user, pl)
     except YouTubeError:
         raise HTTPException(status_code=422, detail="Couldn't read the playlist on YouTube.")
@@ -322,7 +322,7 @@ def push(
             status_code=403, detail="Enable YouTube editing in Settings first."
         )
     try:
-        with quota.attribute(user.id, "playlist_push"):
+        with quota.attribute(user.id, quota.QuotaAction.PLAYLISTS_PUSH):
             plan = plan_push(db, user, pl)
             if plan["units_estimate"] > quota.remaining_today(db):
                 raise HTTPException(
@@ -418,7 +418,7 @@ def delete_playlist(
                 status_code=403, detail="Enable YouTube editing in Settings first."
             )
         try:
-            with quota.attribute(user.id, "playlist_delete"):
+            with quota.attribute(user.id, quota.QuotaAction.PLAYLISTS_DELETE):
                 with YouTubeClient(db, user) as yt:
                     yt.delete_playlist(pl.yt_playlist_id)
         except YouTubeError:

backend/app/routes/sync.py

@@ -41,7 +41,7 @@ def sync_subscriptions(
             detail="Connect your YouTube account (read access) to import subscriptions.",
         )
     before = quota.units_used_today(db)
-    with quota.attribute(user.id, "sync_subscriptions"):
+    with quota.attribute(user.id, quota.QuotaAction.SUBSCRIPTIONS_PULL):
         result = import_subscriptions(db, user)
     result["quota_used_estimate"] = quota.units_used_today(db) - before
     result["quota_remaining_today"] = quota.remaining_today(db)
@@ -63,7 +63,7 @@ def sync_backfill(
     max_channels: int = 25,
 ) -> dict:
     before = quota.units_used_today(db)
-    with quota.attribute(user.id, "backfill_recent"):
+    with quota.attribute(user.id, quota.QuotaAction.VIDEOS_BACKFILL_RECENT):
         result = run_recent_backfill(db, _user_channels(db, user), max_channels=max_channels)
     result["quota_used_estimate"] = quota.units_used_today(db) - before
     return result
@@ -74,7 +74,7 @@ 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, "enrich"):
+    with quota.attribute(user.id, quota.QuotaAction.VIDEOS_ENRICH):
         enriched = run_enrich(db)
     return {
         "enriched": enriched,

backend/app/scheduler.py

@@ -204,7 +204,7 @@ def _rss_job() -> None:
 
 def _enrich_job() -> None:
     def work(db):
-        with quota.attribute(None, "enrich"):
+        with quota.attribute(None, quota.QuotaAction.VIDEOS_ENRICH):
             return run_enrich(db)
 
     _job("enrich", work)
@@ -214,9 +214,9 @@ def _backfill_job() -> None:
     # Recent-first for not-yet-synced channels, then deep backfill for the rest. All
     # background spend is attributed to the system (no actor), split by action.
     def work(db):
-        with quota.attribute(None, "backfill_recent"):
+        with quota.attribute(None, quota.QuotaAction.VIDEOS_BACKFILL_RECENT):
             recent = run_recent_backfill(db, max_channels=25)
-        with quota.attribute(None, "backfill_deep"):
+        with quota.attribute(None, quota.QuotaAction.VIDEOS_BACKFILL_FULL):
             deep = run_deep_backfill(db, max_channels=10)
         return {"recent": recent, "deep": deep}
 
@@ -233,7 +233,7 @@ def _shorts_job() -> None:
 
 def _subscriptions_job() -> None:
     def work(db):
-        with quota.attribute(None, "subscription_resync"):
+        with quota.attribute(None, quota.QuotaAction.SUBSCRIPTIONS_RESYNC):
             return run_subscription_resync(db)
 
     _job("subscriptions", work)
@@ -247,7 +247,7 @@ def _playlist_sync_job() -> None:
 
 def _maintenance_job() -> None:
     def work(db):
-        with quota.attribute(None, "maintenance"):
+        with quota.attribute(None, quota.QuotaAction.MAINTENANCE_REVALIDATE):
             return run_maintenance(db)
 
     _job("maintenance", work)

backend/app/sync/playlists.py

@@ -387,7 +387,7 @@ def sync_all_playlists(db: Session) -> dict:
             progress.report(i, len(users), "playlist_sync")
             continue
         try:
-            with quota.attribute(user.id, "playlist_sync"):
+            with quota.attribute(user.id, quota.QuotaAction.PLAYLISTS_PULL):
                 total += sync_user_playlists(db, user).get("synced", 0)
         except YouTubeError:
             db.rollback()

frontend/src/i18n/locales/de/quotaActions.json

@@ -0,0 +1,16 @@
+{
+  "subscriptions_pull": "Abonnements einlesen",
+  "subscriptions_resync": "Automatische Abo-Resynchronisierung",
+  "playlists_pull": "Playlists einlesen",
+  "playlists_push": "Playlists hochladen",
+  "playlists_delete": "Playlist löschen",
+  "videos_backfill_recent": "Aktuelle Uploads laden",
+  "videos_backfill_full": "Vollständigen Verlauf laden",
+  "videos_enrich": "Video-Anreicherung",
+  "videos_lookup": "Video-Abfrage",
+  "channels_discover": "Kanal-Entdeckung",
+  "channels_subscribe": "Abonnieren",
+  "channels_unsubscribe": "Abo beenden",
+  "maintenance_revalidate": "Wartungs-Neuvalidierung",
+  "other": "Sonstiges"
+}

frontend/src/i18n/locales/en/quotaActions.json

@@ -0,0 +1,16 @@
+{
+  "subscriptions_pull": "Read subscriptions",
+  "subscriptions_resync": "Auto subscription resync",
+  "playlists_pull": "Read playlists",
+  "playlists_push": "Push playlists",
+  "playlists_delete": "Delete playlist",
+  "videos_backfill_recent": "Recent backfill",
+  "videos_backfill_full": "Full-history backfill",
+  "videos_enrich": "Video enrichment",
+  "videos_lookup": "Video lookup",
+  "channels_discover": "Channel discovery",
+  "channels_subscribe": "Subscribe",
+  "channels_unsubscribe": "Unsubscribe",
+  "maintenance_revalidate": "Maintenance re-validation",
+  "other": "Other"
+}

frontend/src/i18n/locales/hu/quotaActions.json

@@ -0,0 +1,16 @@
+{
+  "subscriptions_pull": "Feliratkozások beolvasása",
+  "subscriptions_resync": "Automatikus feliratkozás-újraszinkron",
+  "playlists_pull": "Lejátszási listák beolvasása",
+  "playlists_push": "Lejátszási listák feltöltése",
+  "playlists_delete": "Lejátszási lista törlése",
+  "videos_backfill_recent": "Friss feltöltések betöltése",
+  "videos_backfill_full": "Teljes előzmény betöltése",
+  "videos_enrich": "Videó-gazdagítás",
+  "videos_lookup": "Videó-lekérdezés",
+  "channels_discover": "Csatorna-felfedezés",
+  "channels_subscribe": "Feliratkozás",
+  "channels_unsubscribe": "Leiratkozás",
+  "maintenance_revalidate": "Karbantartó újraellenőrzés",
+  "other": "Egyéb"
+}

frontend/src/lib/format.ts

@@ -44,18 +44,11 @@ export function formatDuration(sec: number | null): string {
   return h > 0 ? `${h}:${pad(m)}:${pad(s)}` : `${m}:${pad(s)}`;
 }
 
-const QUOTA_ACTION_LABELS: Record<string, string> = {
+// Human label for a canonical quota-action key (see backend app.quota.QuotaAction). Resolved
-  sync_subscriptions: "Sync subscriptions",
+// from i18n (quotaActions.<key>) so it's translated in all UI languages; falls back to the raw
-  backfill_recent: "Recent backfill",
+// key for any unmapped/legacy value.
-  backfill_deep: "Full-history backfill",
-  enrich: "Enrichment",
-  unsubscribe: "Unsubscribe",
-  subscription_resync: "Auto subscription resync",
-  api: "Other",
-};
-
 export function quotaActionLabel(action: string): string {
-  return QUOTA_ACTION_LABELS[action] ?? action;
+  return i18n.t(`quotaActions.${action}`, { defaultValue: action });
 }
 
 /** Coarse, human ETA for a remaining duration in seconds ("~3 hours", "~2 days"). */