Merge improvement/tags-ux: tag UX overhaul, user-tags feed widget, video reset, global error dialog

backend/app/routes/feed.py

@@ -435,6 +435,29 @@ def set_video_state(
     return {"video_id": video_id, "status": status}
 
 
+@router.delete("/videos/{video_id}/state")
+def clear_video_state(
+    video_id: str,
+    user: User = Depends(current_user),
+    db: Session = Depends(get_db),
+) -> dict:
+    """Reset a video to pristine for this user — drop the whole VideoState row (status,
+    watch position and watched_at), as if it had never been opened. Saved/playlist membership
+    lives elsewhere and is untouched."""
+    row = db.execute(
+        select(VideoState).where(
+            VideoState.user_id == user.id, VideoState.video_id == video_id
+        )
+    ).scalar_one_or_none()
+    if row is not None:
+        db.delete(row)
+        try:
+            db.commit()
+        except StaleDataError:
+            db.rollback()
+    return {"video_id": video_id, "status": "new", "position_seconds": 0}
+
+
 @router.post("/videos/{video_id}/progress")
 def set_video_progress(
     video_id: str,

backend/app/routes/tags.py

@@ -1,5 +1,6 @@
 from fastapi import APIRouter, Depends, HTTPException
 from sqlalchemy import func, or_, select
+from sqlalchemy.exc import IntegrityError
 from sqlalchemy.orm import Session
 
 from app.auth import current_user
@@ -49,7 +50,11 @@ def create_tag(
         category=category if category in ("language", "topic", "other") else "other",
     )
     db.add(tag)
-    db.commit()
+    try:
+        db.commit()
+    except IntegrityError:
+        db.rollback()
+        raise HTTPException(status_code=409, detail=f"You already have a tag named “{name}”.")
     return {"id": tag.id, "name": tag.name, "color": tag.color, "category": tag.category}
 
 
@@ -76,7 +81,11 @@ def update_tag(
         tag.name = name
     if "color" in payload:
         tag.color = payload.get("color")
-    db.commit()
+    try:
+        db.commit()
+    except IntegrityError:
+        db.rollback()
+        raise HTTPException(status_code=409, detail=f"You already have a tag named “{tag.name}”.")
     return {"id": tag.id, "name": tag.name, "color": tag.color, "category": tag.category}
 
 

frontend/src/App.tsx

@@ -32,6 +32,7 @@ import SettingsPanel from "./components/SettingsPanel";
 import OnboardingWizard from "./components/OnboardingWizard";
 import { shouldAutoOpenOnboarding } from "./lib/onboarding";
 import Toaster from "./components/Toaster";
+import ErrorDialog from "./components/ErrorDialog";
 import About from "./components/About";
 import ReleaseNotes from "./components/ReleaseNotes";
 import VersionBanner from "./components/VersionBanner";
@@ -108,6 +109,16 @@ export default function App() {
   const [aboutOpen, setAboutOpen] = useState(false);
   const [notesOpen, setNotesOpen] = useState(false);
   const [notesHighlight, setNotesHighlight] = useState<string | undefined>(undefined);
+  // "Focus this channel in the manager": jump to the Channels page and seed its name filter
+  // so the channel is isolated. Cleared when leaving the page so it doesn't re-apply later.
+  const [focusChannelName, setFocusChannelName] = useState<string | null>(null);
+  const focusChannel = (name: string) => {
+    setFocusChannelName(name);
+    setPage("channels");
+  };
+  useEffect(() => {
+    if (page !== "channels") setFocusChannelName(null);
+  }, [page]);
 
   function openReleaseNotes(highlight?: string) {
     setNotesHighlight(highlight);
@@ -271,6 +282,7 @@ export default function App() {
               setFilters={setFilters}
               layout={sidebarLayout}
               setLayout={setSidebarLayout}
+              onFocusChannel={focusChannel}
             />
           )}
           <main className="flex-1 min-w-0 overflow-y-auto">
@@ -278,6 +290,8 @@ export default function App() {
             <Channels
               canWrite={meQuery.data!.can_write}
               isAdmin={meQuery.data!.role === "admin"}
+              focusChannelName={focusChannelName}
+              onFocusChannel={focusChannel}
               statusFilter={channelFilter}
               setStatusFilter={setChannelFilter}
               onOpenWizard={() => setWizardOpen(true)}
@@ -285,6 +299,11 @@ export default function App() {
                 setFilters({ ...filters, channelId: id, channelName: name, show: "all" });
                 setPage("feed");
               }}
+              onFilterByTag={(tagId, name) => {
+                setFilters({ ...filters, tags: [tagId], channelId: undefined, channelName: undefined });
+                setPage("feed");
+                notify({ level: "info", message: t("channels.notify.filteredByTag", { name }) });
+              }}
             />
           ) : page === "stats" && meQuery.data!.role === "admin" ? (
             <Stats />
@@ -333,6 +352,7 @@ export default function App() {
       {notesOpen && (
         <ReleaseNotes onClose={() => setNotesOpen(false)} highlight={notesHighlight} />
       )}
+      <ErrorDialog />
     </div>
   );
 }

frontend/src/components/Channels.tsx

@@ -9,10 +9,10 @@ import {
   Eye,
   EyeOff,
   History,
+  Pencil,
   Plus,
   RefreshCw,
   UserMinus,
-  X,
 } from "lucide-react";
 import { api, HttpError, type ManagedChannel, type Tag } from "../lib/api";
 import { formatEta, formatViews, relativeTime } from "../lib/format";
@@ -20,6 +20,7 @@ import { notify } from "../lib/notifications";
 import Tooltip from "./Tooltip";
 import Avatar from "./Avatar";
 import DataTable, { type Column } from "./DataTable";
+import TagManager from "./TagManager";
 import { useConfirm } from "./ConfirmProvider";
 
 export type ChannelStatusFilter = "all" | "needs_full" | "fully_synced" | "hidden";
@@ -42,6 +43,9 @@ export default function Channels({
   canWrite,
   isAdmin,
   onViewChannel,
+  onFilterByTag,
+  onFocusChannel,
+  focusChannelName,
   statusFilter,
   setStatusFilter,
   onOpenWizard,
@@ -49,6 +53,9 @@ export default function Channels({
   canWrite: boolean;
   isAdmin: boolean;
   onViewChannel: (id: string, name: string) => void;
+  onFilterByTag: (tagId: number, name: string) => void;
+  onFocusChannel: (name: string) => void;
+  focusChannelName: string | null;
   statusFilter: ChannelStatusFilter;
   setStatusFilter: (f: ChannelStatusFilter) => void;
   onOpenWizard: () => void;
@@ -73,7 +80,7 @@ export default function Channels({
   const channelsQuery = useQuery({ queryKey: ["channels"], queryFn: api.channels });
   const tagsQuery = useQuery({ queryKey: ["tags"], queryFn: api.tags });
   const statusQuery = useQuery({ queryKey: ["my-status"], queryFn: api.myStatus });
-  const [newTag, setNewTag] = useState("");
+  const [tagManagerOpen, setTagManagerOpen] = useState(false);
 
   const invalidate = () => {
     qc.invalidateQueries({ queryKey: ["channels"] });
@@ -138,17 +145,6 @@ export default function Channels({
     },
     onError: (e) => notifyActionError(e, "channels.notify.syncFailed"),
   });
-  const createTag = useMutation({
-    mutationFn: (name: string) => api.createTag({ name, category: "other" }),
-    onSuccess: () => {
-      setNewTag("");
-      qc.invalidateQueries({ queryKey: ["tags"] });
-    },
-  });
-  const deleteTag = useMutation({
-    mutationFn: (id: number) => api.deleteTag(id),
-    onSuccess: () => invalidate(),
-  });
   const unsubscribe = useMutation({
     mutationFn: (id: string) => api.unsubscribeChannel(id),
     onSuccess: () => {
@@ -307,6 +303,7 @@ export default function Channels({
           c={c}
           userTags={userTags}
           onToggleTag={(tagId) => toggleTag(c.id, tagId, c.tag_ids.includes(tagId))}
+          onTagClick={onFilterByTag}
         />
       ),
     },
@@ -427,42 +424,32 @@ export default function Channels({
         />
       </p>
 
-      {/* Your tags */}
+      {/* Your tags — read-only overview; add/rename/delete live in the manager dialog. */}
       <div className="flex flex-wrap items-center gap-1.5 mb-4">
         <Tooltip hint={t("channels.tags.yourTagsHint")}>
           <span className="text-xs uppercase tracking-wide text-muted mr-1 cursor-help underline decoration-dotted decoration-muted/40 underline-offset-4">
             {t("channels.tags.yourTags")}
           </span>
         </Tooltip>
-        {userTags.map((t) => (
+        {userTags.map((tg) => (
           <span
-            key={t.id}
+            key={tg.id}
-            className="inline-flex items-center gap-1 text-xs px-2 py-1 rounded-full bg-card border border-border"
+            className="text-xs px-2 py-1 rounded-full bg-card border border-border"
           >
-            {t.name}
+            {tg.name}
-            <button onClick={() => deleteTag.mutate(t.id)} className="text-muted hover:text-red-400">
-              <X className="w-3 h-3" />
-            </button>
           </span>
         ))}
-        <form
+        <button
-          onSubmit={(e) => {
+          onClick={() => setTagManagerOpen(true)}
-            e.preventDefault();
+          className="inline-flex items-center gap-1 text-xs px-2 py-1 rounded-full border border-dashed border-border text-muted hover:text-accent hover:border-accent transition"
-            if (newTag.trim()) createTag.mutate(newTag.trim());
-          }}
-          className="inline-flex items-center gap-1"
         >
-          <input
+          <Pencil className="w-3 h-3" />
-            value={newTag}
+          {t("channels.tags.manage")}
-            onChange={(e) => setNewTag(e.target.value)}
+        </button>
-            placeholder={t("channels.tags.newTag")}
-            className="w-24 bg-card border border-border rounded-full px-2.5 py-1 text-xs outline-none focus:border-accent"
-          />
-          <button type="submit" className="text-muted hover:text-accent" title={t("channels.tags.createTag")}>
-            <Plus className="w-4 h-4" />
-          </button>
-        </form>
       </div>
+      {tagManagerOpen && (
+        <TagManager onClose={() => setTagManagerOpen(false)} onFocusChannel={onFocusChannel} />
+      )}
 
       {/* Channel table */}
       {channelsQuery.isLoading ? (
@@ -475,6 +462,7 @@ export default function Channels({
           persistKey="siftlode.channelsTable"
           controlsPosition="top"
           controlsLeading={statusChips}
+          externalFilter={focusChannelName ? { key: "channel", value: focusChannelName } : null}
           rowClassName={(c) => (c.hidden ? "opacity-60" : "")}
           emptyText={t("channels.empty")}
         />
@@ -605,10 +593,12 @@ function TagsCell({
   c,
   userTags,
   onToggleTag,
+  onTagClick,
 }: {
   c: ManagedChannel;
   userTags: Tag[];
   onToggleTag: (tagId: number) => void;
+  onTagClick: (tagId: number, name: string) => void;
 }) {
   const { t } = useTranslation();
   const [open, setOpen] = useState(false);
@@ -634,12 +624,14 @@ function TagsCell({
   return (
     <div ref={ref} className="relative flex flex-wrap items-center gap-1 min-w-[160px]">
       {attached.map((tg) => (
-        <span
+        <button
           key={tg.id}
-          className="text-[10px] px-1.5 py-0.5 rounded-full bg-accent text-accent-fg border border-accent"
+          onClick={() => onTagClick(tg.id, tg.name)}
+          title={t("channels.row.filterFeedByTag", { name: tg.name })}
+          className="text-[10px] px-1.5 py-0.5 rounded-full bg-accent text-accent-fg border border-accent hover:opacity-80 transition"
         >
           {tg.name}
-        </span>
+        </button>
       ))}
       <button
         onClick={() => setOpen((o) => !o)}

frontend/src/components/DataTable.tsx

@@ -66,6 +66,7 @@ export default function DataTable<T>({
   rowClassName,
   controlsPosition = "bottom",
   controlsLeading,
+  externalFilter,
 }: {
   rows: T[];
   columns: Column<T>[];
@@ -77,6 +78,9 @@ export default function DataTable<T>({
   rowClassName?: (row: T) => string;
   controlsPosition?: "top" | "bottom" | "both";
   controlsLeading?: ReactNode;
+  // Set a column's filter from outside (e.g. "focus this channel" deep-links here). Applied
+  // whenever its value changes; the user can still clear it from the header afterwards.
+  externalFilter?: { key: string; value: string } | null;
 }) {
   const { t } = useTranslation();
   const initial = loadPersist(persistKey);
@@ -93,6 +97,13 @@ export default function DataTable<T>({
     if (persistKey) localStorage.setItem(persistKey, JSON.stringify({ sort, filters, page, size }));
   }, [persistKey, sort, filters, page, size]);
 
+  useEffect(() => {
+    if (!externalFilter) return;
+    setFilters((f) => ({ ...f, [externalFilter.key]: externalFilter.value }));
+    setPage(0);
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [externalFilter?.key, externalFilter?.value]);
+
   useEffect(() => {
     if (!openFilter) return;
     function onDown(e: MouseEvent) {

frontend/src/components/ErrorDialog.tsx

@@ -0,0 +1,24 @@
+import { useSyncExternalStore } from "react";
+import { useTranslation } from "react-i18next";
+import { dismissError, getError, subscribeError } from "../lib/errorDialog";
+import Modal from "./Modal";
+
+// Renders the current app error (if any) as a modal the user must acknowledge.
+export default function ErrorDialog() {
+  const { t } = useTranslation();
+  const err = useSyncExternalStore(subscribeError, getError, getError);
+  if (!err) return null;
+  return (
+    <Modal title={err.title} onClose={dismissError} maxWidth="max-w-md">
+      <p className="text-sm leading-relaxed text-fg/90">{err.message}</p>
+      <div className="flex justify-end mt-5">
+        <button
+          onClick={dismissError}
+          className="px-4 py-2 rounded-lg bg-accent text-accent-fg text-sm font-medium hover:opacity-90 transition"
+        >
+          {t("errors.ok")}
+        </button>
+      </div>
+    </Modal>
+  );
+}

frontend/src/components/Feed.tsx

@@ -185,6 +185,25 @@ export default function Feed({
     [qc]
   );
 
+  const onResetState = useCallback(
+    (id: string) => {
+      // Reset to pristine (drop the whole VideoState row, incl. resume position) — the
+      // un-watch toggle can't clear an in-progress position, this can.
+      setOverrides((o) => ({ ...o, [id]: "new" }));
+      api
+        .clearState(id)
+        .then(() => qc.invalidateQueries({ queryKey: ["feed"] }))
+        .catch(() =>
+          setOverrides((o) => {
+            const next = { ...o };
+            delete next[id];
+            return next;
+          })
+        );
+    },
+    [qc]
+  );
+
   const onChannelFilter = useCallback(
     (channelId: string, channelName: string) => {
       setFilters({ ...filters, channelId, channelName });
@@ -363,6 +382,7 @@ export default function Feed({
               onState={onState}
               onToggleSave={onToggleSave}
               onChannelFilter={onChannelFilter}
+              onResetState={onResetState}
               onOpen={openVideo}
             />
           ))}
@@ -377,6 +397,7 @@ export default function Feed({
               onState={onState}
               onToggleSave={onToggleSave}
               onChannelFilter={onChannelFilter}
+              onResetState={onResetState}
               onOpen={openVideo}
             />
           ))}

frontend/src/components/Modal.tsx

@@ -1,7 +1,12 @@
-import { useEffect, type ReactNode } from "react";
+import { useEffect, useRef, type ReactNode } from "react";
 import { createPortal } from "react-dom";
 import { X } from "lucide-react";
 
+// Stack of open modals so ESC only closes the topmost one — e.g. an error dialog over the
+// tag editor: pressing ESC dismisses just the error and returns to the editor underneath.
+let modalStack: number[] = [];
+let nextModalId = 1;
+
 // Small centered modal shell (portaled to <body>): backdrop + ESC + scroll-lock close.
 export default function Modal({
   title,
@@ -14,18 +19,27 @@ export default function Modal({
   children: ReactNode;
   maxWidth?: string;
 }) {
+  // Keep a stable handler across renders so the stack id is assigned once per mount.
+  const onCloseRef = useRef(onClose);
+  onCloseRef.current = onClose;
   useEffect(() => {
+    const id = nextModalId++;
+    modalStack.push(id);
     const onKey = (e: KeyboardEvent) => {
-      if (e.key === "Escape") onClose();
+      if (e.key === "Escape" && modalStack[modalStack.length - 1] === id) {
+        e.stopPropagation();
+        onCloseRef.current();
+      }
     };
     window.addEventListener("keydown", onKey);
     const prev = document.body.style.overflow;
     document.body.style.overflow = "hidden";
     return () => {
       window.removeEventListener("keydown", onKey);
+      modalStack = modalStack.filter((x) => x !== id);
       document.body.style.overflow = prev;
     };
-  }, [onClose]);
+  }, []);
 
   return createPortal(
     <div

frontend/src/components/Sidebar.tsx

@@ -36,6 +36,7 @@ import {
 } from "../lib/sidebarLayout";
 import { shareUrl } from "../lib/urlState";
 import { notify } from "../lib/notifications";
+import TagManager from "./TagManager";
 
 // Filter ids; display labels resolved at render time via t("sidebar.sort.<id>") etc.
 const SORT_IDS = [
@@ -114,11 +115,13 @@ export default function Sidebar({
   setFilters,
   layout,
   setLayout,
+  onFocusChannel,
 }: {
   filters: FeedFilters;
   setFilters: (f: FeedFilters) => void;
   layout: SidebarLayout;
   setLayout: (l: SidebarLayout) => void;
+  onFocusChannel: (name: string) => void;
 }) {
   const { t } = useTranslation();
   const tagsQuery = useQuery({ queryKey: ["tags"], queryFn: api.tags });
@@ -172,7 +175,11 @@ export default function Sidebar({
       : t("sidebar.thisChannel"));
   const languages = tags.filter((t) => t.category === "language");
   const topics = tags.filter((t) => t.category === "topic");
+  // The user's own (non-system) tags — those assigned to channels in the Channel manager.
+  // Facets only cover language/topic, so these show their static channel_count.
+  const userTags = tags.filter((t) => !t.system);
   const [customDates, setCustomDates] = useState(false);
+  const [tagManagerOpen, setTagManagerOpen] = useState(false);
   const [editing, setEditing] = useState(false);
 
   const sensors = useSensors(
@@ -217,6 +224,7 @@ export default function Sidebar({
     date: true,
     language: languages.length > 0,
     topic: topics.length > 0,
+    tags: userTags.length > 0,
   };
 
   function toggleCollapse(id: WidgetId) {
@@ -393,6 +401,28 @@ export default function Sidebar({
           </>
         );
       }
+      case "tags":
+        return (
+          <div className="flex flex-wrap items-center gap-1.5">
+            {userTags.map((tg) => (
+              <TagChip
+                key={tg.id}
+                tag={tg}
+                count={tg.channel_count}
+                active={filters.tags.includes(tg.id)}
+                onClick={() => toggleTag(tg.id)}
+              />
+            ))}
+            <button
+              onClick={() => setTagManagerOpen(true)}
+              title={t("sidebar.manageTags")}
+              className="inline-flex items-center gap-1 text-xs px-2 py-1 rounded-full border border-dashed border-border text-muted hover:text-accent hover:border-accent transition"
+            >
+              <Pencil className="w-3 h-3" />
+              {t("sidebar.manageTags")}
+            </button>
+          </div>
+        );
     }
   }
 
@@ -496,6 +526,9 @@ export default function Sidebar({
           </div>
         </SortableContext>
       </DndContext>
+      {tagManagerOpen && (
+        <TagManager onClose={() => setTagManagerOpen(false)} onFocusChannel={onFocusChannel} />
+      )}
     </aside>
   );
 }

frontend/src/components/TagManager.tsx

@@ -0,0 +1,213 @@
+import { useRef, useState } from "react";
+import { createPortal } from "react-dom";
+import { useTranslation } from "react-i18next";
+import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
+import { Plus, Trash2 } from "lucide-react";
+import { api, type Tag } from "../lib/api";
+import { notify } from "../lib/notifications";
+import Modal from "./Modal";
+import { useConfirm } from "./ConfirmProvider";
+
+// One editable row: rename in place (commit on Enter/blur), delete with a confirm, and a
+// hover popover on the count listing the tagged channels (each a link that focuses it in the
+// Channel manager). The popover is portaled to <body> so the list's own scroll can't clip it.
+function TagRow({
+  tag,
+  channels,
+  onRename,
+  onDelete,
+  onPickChannel,
+}: {
+  tag: Tag;
+  channels: { id: string; title: string }[];
+  onRename: (name: string) => void;
+  onDelete: () => void;
+  onPickChannel: (name: string) => void;
+}) {
+  const { t } = useTranslation();
+  const [name, setName] = useState(tag.name);
+  const [open, setOpen] = useState(false);
+  const [pos, setPos] = useState({ left: 0, top: 0 });
+  const countRef = useRef<HTMLSpanElement | null>(null);
+  const closeTimer = useRef<number | undefined>(undefined);
+  const commit = () => {
+    const v = name.trim();
+    if (v && v !== tag.name) onRename(v);
+    else setName(tag.name);
+  };
+  const openPop = () => {
+    window.clearTimeout(closeTimer.current);
+    if (channels.length === 0) return;
+    const r = countRef.current?.getBoundingClientRect();
+    if (r) setPos({ left: r.right + 8, top: r.top });
+    setOpen(true);
+  };
+  const closeSoon = () => {
+    closeTimer.current = window.setTimeout(() => setOpen(false), 150);
+  };
+  return (
+    <div className="flex items-center gap-2">
+      <input
+        value={name}
+        onChange={(e) => setName(e.target.value)}
+        onBlur={commit}
+        onKeyDown={(e) => e.key === "Enter" && (e.target as HTMLInputElement).blur()}
+        className="flex-1 min-w-0 bg-card border border-border rounded-md px-2 py-1.5 text-sm outline-none focus:border-accent"
+      />
+      <span
+        ref={countRef}
+        onMouseEnter={openPop}
+        onMouseLeave={closeSoon}
+        className={`text-xs text-muted tabular-nums shrink-0 ${
+          channels.length
+            ? "cursor-help underline decoration-dotted decoration-muted/40 underline-offset-2"
+            : ""
+        }`}
+      >
+        {t("tagManager.channels", { count: tag.channel_count })}
+      </span>
+      <button
+        onClick={onDelete}
+        title={t("tagManager.delete")}
+        aria-label={t("tagManager.delete")}
+        className="shrink-0 p-1.5 rounded-md text-muted hover:text-red-400 transition"
+      >
+        <Trash2 className="w-4 h-4" />
+      </button>
+      {open &&
+        createPortal(
+          <div
+            onMouseEnter={openPop}
+            onMouseLeave={closeSoon}
+            style={{ position: "fixed", left: pos.left, top: pos.top, zIndex: 60 }}
+            className="glass-menu w-56 max-h-72 overflow-y-auto rounded-xl p-1.5 animate-[popIn_0.16s_ease]"
+          >
+            <div className="text-[11px] uppercase tracking-wide text-muted px-2 py-1">
+              {t("tagManager.onChannels")}
+            </div>
+            {channels.map((ch) => (
+              <button
+                key={ch.id}
+                onClick={() => onPickChannel(ch.title)}
+                className="w-full text-left text-sm px-2 py-1.5 rounded-md text-muted hover:text-fg hover:bg-card truncate transition"
+              >
+                {ch.title}
+              </button>
+            ))}
+          </div>,
+          document.body
+        )}
+    </div>
+  );
+}
+
+export default function TagManager({
+  onClose,
+  onFocusChannel,
+}: {
+  onClose: () => void;
+  onFocusChannel: (name: string) => void;
+}) {
+  const { t } = useTranslation();
+  const qc = useQueryClient();
+  const confirm = useConfirm();
+  const [newName, setNewName] = useState("");
+  const tagsQuery = useQuery({ queryKey: ["tags"], queryFn: api.tags });
+  const channelsQuery = useQuery({ queryKey: ["channels"], queryFn: api.channels });
+  const userTags = (tagsQuery.data ?? []).filter((tg) => !tg.system);
+  const channelsForTag = (tagId: number) =>
+    (channelsQuery.data ?? [])
+      .filter((c) => c.tag_ids.includes(tagId))
+      .map((c) => ({ id: c.id, title: c.title ?? c.id }));
+
+  const invalidate = () => {
+    qc.invalidateQueries({ queryKey: ["tags"] });
+    qc.invalidateQueries({ queryKey: ["channels"] });
+    qc.invalidateQueries({ queryKey: ["feed"] });
+  };
+  const create = useMutation({
+    mutationFn: (name: string) => api.createTag({ name, category: "other" }),
+    onSuccess: () => {
+      setNewName("");
+      invalidate();
+    },
+  });
+  const rename = useMutation({
+    mutationFn: (v: { id: number; name: string }) => api.updateTag(v.id, { name: v.name }),
+    onSuccess: invalidate,
+  });
+  const del = useMutation({
+    mutationFn: (id: number) => api.deleteTag(id),
+    onSuccess: () => {
+      invalidate();
+      notify({ level: "success", message: t("tagManager.deleted") });
+    },
+  });
+
+  // Picking a channel from a tag's popover: close the dialog, then focus it in the manager.
+  const pickChannel = (name: string) => {
+    onClose();
+    onFocusChannel(name);
+  };
+
+  return (
+    <Modal title={t("tagManager.title")} onClose={onClose}>
+      <div className="flex flex-col gap-2">
+        {userTags.length === 0 ? (
+          <p className="text-sm text-muted">{t("tagManager.empty")}</p>
+        ) : (
+          // Cap at ~8 rows tall, then scroll — the list can grow long.
+          <div className="flex flex-col gap-2 max-h-[22rem] overflow-y-auto pr-1">
+            {userTags.map((tag) => (
+              <TagRow
+                key={tag.id}
+                tag={tag}
+                channels={channelsForTag(tag.id)}
+                onPickChannel={pickChannel}
+                onRename={(name) => rename.mutate({ id: tag.id, name })}
+                onDelete={async () => {
+                  // Only confirm when the tag is actually in use; an unused tag deletes outright.
+                  if (tag.channel_count > 0) {
+                    const ok = await confirm({
+                      title: t("tagManager.deleteTitle"),
+                      message: t("tagManager.confirmDelete", {
+                        name: tag.name,
+                        count: tag.channel_count,
+                      }),
+                      confirmLabel: t("tagManager.delete"),
+                      danger: true,
+                    });
+                    if (!ok) return;
+                  }
+                  del.mutate(tag.id);
+                }}
+              />
+            ))}
+          </div>
+        )}
+        <form
+          onSubmit={(e) => {
+            e.preventDefault();
+            if (newName.trim()) create.mutate(newName.trim());
+          }}
+          className="flex items-center gap-2 mt-2 pt-3 border-t border-border"
+        >
+          <Plus className="w-4 h-4 text-muted shrink-0" />
+          <input
+            value={newName}
+            onChange={(e) => setNewName(e.target.value)}
+            placeholder={t("tagManager.newPlaceholder")}
+            className="flex-1 min-w-0 bg-card border border-border rounded-md px-2 py-1.5 text-sm outline-none focus:border-accent"
+          />
+          <button
+            type="submit"
+            disabled={!newName.trim()}
+            className="shrink-0 px-3 py-1.5 rounded-md border border-border text-sm text-muted enabled:hover:text-fg enabled:hover:border-accent disabled:opacity-40 transition"
+          >
+            {t("tagManager.add")}
+          </button>
+        </form>
+      </div>
+    </Modal>
+  );
+}

frontend/src/components/VideoCard.tsx

@@ -19,11 +19,13 @@ import { formatDuration, formatViews, relativeTime } from "../lib/format";
 function Actions({
   video,
   onState,
+  onResetState,
   onToggleSave,
   onChannelFilter,
 }: {
   video: Video;
   onState: (id: string, status: string) => void;
+  onResetState?: (id: string) => void;
   onToggleSave: (id: string, saved: boolean) => void;
   onChannelFilter?: (channelId: string, channelName: string) => void;
 }) {
@@ -33,6 +35,9 @@ function Actions({
     e.stopPropagation();
     onState(video.id, video.status === status ? "new" : status);
   };
+  // Pristine = never opened: default status and no resume position. The reset clears the
+  // whole state (incl. an in-progress position the un-watch toggle can't touch).
+  const resettable = video.status !== "new" || video.position_seconds > 0;
   const toggleSave = (e: React.MouseEvent) => {
     e.preventDefault();
     e.stopPropagation();
@@ -79,6 +84,19 @@ function Actions({
           <EyeOff className="w-4 h-4" />
         )}
       </button>
+      {onResetState && resettable && (
+        <button
+          onClick={(e) => {
+            e.preventDefault();
+            e.stopPropagation();
+            onResetState(video.id);
+          }}
+          title={t("card.resetState")}
+          className="p-1.5 rounded-md hover:bg-surface text-muted hover:text-fg"
+        >
+          <RotateCcw className="w-4 h-4" />
+        </button>
+      )}
       {onChannelFilter && (
         <button
           onClick={(e) => {
@@ -224,6 +242,7 @@ function VideoCard({
   video,
   view,
   onState,
+  onResetState,
   onToggleSave,
   onChannelFilter,
   onOpen,
@@ -231,6 +250,7 @@ function VideoCard({
   video: Video;
   view: "grid" | "list";
   onState: (id: string, status: string) => void;
+  onResetState?: (id: string) => void;
   onToggleSave: (id: string, saved: boolean) => void;
   onChannelFilter?: (channelId: string, channelName: string) => void;
   onOpen?: (v: Video, startAt?: number | null) => void;
@@ -294,7 +314,7 @@ function VideoCard({
           </a>
           <div className="text-xs text-muted mt-0.5">{meta}</div>
         </div>
-        <Actions video={video} onState={onState} onToggleSave={onToggleSave} onChannelFilter={onChannelFilter} />
+        <Actions video={video} onState={onState} onResetState={onResetState} onToggleSave={onToggleSave} onChannelFilter={onChannelFilter} />
       </div>
     );
   }
@@ -325,7 +345,7 @@ function VideoCard({
             {video.channel_title}
           </a>
           <div className="text-xs text-muted mt-0.5">{meta}</div>
-          <Actions video={video} onState={onState} onToggleSave={onToggleSave} onChannelFilter={onChannelFilter} />
+          <Actions video={video} onState={onState} onResetState={onResetState} onToggleSave={onToggleSave} onChannelFilter={onChannelFilter} />
         </div>
       </div>
     </div>

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

@@ -8,6 +8,7 @@
   "unhide": "Einblenden",
   "hide": "Ausblenden",
   "onlyThisChannel": "Nur dieser Kanal",
+  "resetState": "Zurücksetzen — Fortschritt/Status löschen",
   "thisChannel": "Dieser Kanal",
   "continueTitle": "Dort fortsetzen, wo du aufgehört hast",
   "continue": "Fortsetzen",

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

@@ -13,6 +13,7 @@
   },
   "tags": {
     "yourTags": "Deine Tags",
+    "manage": "Tags verwalten",
     "yourTagsHint": "Deine persönlichen Labels. Hänge sie unten an Kanäle an und filtere den Feed dann über die Seitenleiste nach Tag. (Getrennt von den automatischen Sprach-/Themen-Tags.)",
     "newTag": "neuer Tag",
     "createTag": "Tag erstellen"
@@ -56,6 +57,7 @@
     "subs": "{{formatted}} Abonnenten",
     "openOnYouTube": "Auf YouTube öffnen",
     "editTags": "Tags bearbeiten",
+    "filterFeedByTag": "Feed nach „{{name}}“ filtern",
     "priorityHint": "Deine Einstufung für diesen Kanal. Sortiere den Feed nach „Kanalpriorität“, um Kanäle mit höherer Priorität nach oben zu bringen.",
     "raisePriority": "Priorität erhöhen",
     "lowerPriority": "Priorität senken",
@@ -94,6 +96,7 @@
     "fullHistoryFailed": "Vollständiger Verlauf konnte nicht angefordert werden",
     "needYouTube": "Verbinde dein YouTube-Konto, um dies zu tun.",
     "connect": "Verbinden",
+    "filteredByTag": "Feed nach Tag gefiltert: {{name}}",
     "resetDone": "Kanal zurückgesetzt — wird neu geladen",
     "resetFailed": "Kanal konnte nicht zurückgesetzt werden"
   },

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

@@ -1,4 +1,8 @@
 {
+  "title": "Nicht möglich",
+  "generic": "Der Server konnte die Aktion nicht ausführen. Bitte erneut versuchen.",
+  "server": "Serverfehler",
+  "ok": "OK",
   "boundary": {
     "title": "Etwas ist schiefgelaufen.",
     "subtitle": "Die App ist auf einen unerwarteten Fehler gestoßen.",

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

@@ -26,6 +26,7 @@
   "clearDates": "Daten löschen",
   "reshuffle": "Neu mischen",
   "noMatchingTags": "Keine passenden Tags",
+  "manageTags": "Verwalten",
   "shareView": "Link zu dieser Ansicht kopieren",
   "shareCopied": "Ansichts-Link in die Zwischenablage kopiert",
   "shareFailed": "Link konnte nicht kopiert werden",
@@ -35,7 +36,8 @@
     "date": "Upload-Datum",
     "content": "Inhaltstyp",
     "language": "Sprache",
-    "topic": "Thema"
+    "topic": "Thema",
+    "tags": "Deine Tags"
   },
   "show": {
     "unwatched": "Ungesehen",

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

@@ -0,0 +1,12 @@
+{
+  "title": "Tags verwalten",
+  "channels": "{{count}} Kan.",
+  "onChannels": "Getaggte Kanäle",
+  "delete": "Löschen",
+  "deleted": "Tag gelöscht",
+  "deleteTitle": "Tag löschen",
+  "confirmDelete": "Tag „{{name}}“ löschen? Er wird von allen Kanälen entfernt, auf denen er liegt.",
+  "empty": "Noch keine Tags — füge unten einen hinzu.",
+  "newPlaceholder": "Neuer Tag-Name…",
+  "add": "Hinzufügen"
+}

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

@@ -8,6 +8,7 @@
   "unhide": "Unhide",
   "hide": "Hide",
   "onlyThisChannel": "Only this channel",
+  "resetState": "Reset — clear watch progress/status",
   "thisChannel": "This channel",
   "continueTitle": "Continue where you left off",
   "continue": "Continue",

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

@@ -13,6 +13,7 @@
   },
   "tags": {
     "yourTags": "Your tags",
+    "manage": "Manage tags",
     "yourTagsHint": "Your personal labels. Attach them to channels below, then filter the feed by tag from the sidebar. (Separate from the automatic language/topic tags.)",
     "newTag": "new tag",
     "createTag": "Create tag"
@@ -56,6 +57,7 @@
     "subs": "{{formatted}} subs",
     "openOnYouTube": "Open on YouTube",
     "editTags": "Edit tags",
+    "filterFeedByTag": "Filter the feed by “{{name}}”",
     "priorityHint": "Your ranking for this channel. Sort the feed by “Channel priority” to bring higher-priority channels to the top.",
     "raisePriority": "Raise priority",
     "lowerPriority": "Lower priority",
@@ -94,6 +96,7 @@
     "fullHistoryFailed": "Couldn't request full history",
     "needYouTube": "Connect your YouTube account to do this.",
     "connect": "Connect",
+    "filteredByTag": "Feed filtered by tag: {{name}}",
     "resetDone": "Channel reset — re-fetching now",
     "resetFailed": "Couldn't reset this channel"
   },

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

@@ -1,4 +1,8 @@
 {
+  "title": "Couldn't complete that",
+  "generic": "The server couldn't carry out that action. Please try again.",
+  "server": "Server error",
+  "ok": "OK",
   "boundary": {
     "title": "Something went wrong.",
     "subtitle": "The app hit an unexpected error.",

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

@@ -26,6 +26,7 @@
   "clearDates": "clear dates",
   "reshuffle": "Reshuffle",
   "noMatchingTags": "No matching tags here",
+  "manageTags": "Manage",
   "shareView": "Copy a link to this view",
   "shareCopied": "View link copied to clipboard",
   "shareFailed": "Couldn't copy the link",
@@ -35,7 +36,8 @@
     "date": "Upload date",
     "content": "Content type",
     "language": "Language",
-    "topic": "Topic"
+    "topic": "Topic",
+    "tags": "Your tags"
   },
   "show": {
     "unwatched": "Unwatched",

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

@@ -0,0 +1,12 @@
+{
+  "title": "Manage tags",
+  "channels": "{{count}} ch.",
+  "onChannels": "Tagged channels",
+  "delete": "Delete",
+  "deleted": "Tag deleted",
+  "deleteTitle": "Delete tag",
+  "confirmDelete": "Delete the tag “{{name}}”? It will be removed from every channel it's on.",
+  "empty": "No tags yet — add one below.",
+  "newPlaceholder": "New tag name…",
+  "add": "Add"
+}

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

@@ -8,6 +8,7 @@
   "unhide": "Megjelenítés",
   "hide": "Elrejtés",
   "onlyThisChannel": "Csak ez a csatorna",
+  "resetState": "Alaphelyzet — nézési előzmény/státusz törlése",
   "thisChannel": "Ez a csatorna",
   "continueTitle": "Folytatás ott, ahol abbahagytad",
   "continue": "Folytatás",

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

@@ -13,6 +13,7 @@
   },
   "tags": {
     "yourTags": "Címkéid",
+    "manage": "Címkék kezelése",
     "yourTagsHint": "Saját személyes címkéid. Csatold őket az alábbi csatornákhoz, majd szűrd a hírfolyamot címke szerint az oldalsávból. (Az automatikus nyelvi/téma címkéktől függetlenül.)",
     "newTag": "új címke",
     "createTag": "Címke létrehozása"
@@ -56,6 +57,7 @@
     "subs": "{{formatted}} feliratkozó",
     "openOnYouTube": "Megnyitás a YouTube-on",
     "editTags": "Címkék szerkesztése",
+    "filterFeedByTag": "Hírfolyam szűrése: „{{name}}”",
     "priorityHint": "A te rangsorod ehhez a csatornához. Rendezd a hírfolyamot „Csatorna prioritás” szerint, hogy a magasabb prioritású csatornák felülre kerüljenek.",
     "raisePriority": "Prioritás növelése",
     "lowerPriority": "Prioritás csökkentése",
@@ -94,6 +96,7 @@
     "fullHistoryFailed": "Nem sikerült teljes előzményt kérni",
     "needYouTube": "Ehhez csatlakoztasd a YouTube-fiókod.",
     "connect": "Csatlakoztatás",
+    "filteredByTag": "Hírfolyam szűrve címkére: {{name}}",
     "resetDone": "Csatorna resetelve — újraletöltés folyamatban",
     "resetFailed": "Nem sikerült resetelni a csatornát"
   },

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

@@ -1,4 +1,8 @@
 {
+  "title": "Nem sikerült",
+  "generic": "A szerver nem tudta végrehajtani a műveletet. Próbáld újra.",
+  "server": "Szerverhiba",
+  "ok": "OK",
   "boundary": {
     "title": "Hiba történt.",
     "subtitle": "Az alkalmazás váratlan hibába ütközött.",

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

@@ -26,6 +26,7 @@
   "clearDates": "dátumok törlése",
   "reshuffle": "Újrakeverés",
   "noMatchingTags": "Nincs ide illő címke",
+  "manageTags": "Kezelés",
   "shareView": "Hivatkozás másolása erre a nézetre",
   "shareCopied": "Nézet-hivatkozás a vágólapra másolva",
   "shareFailed": "Nem sikerült a hivatkozás másolása",
@@ -35,7 +36,8 @@
     "date": "Feltöltés dátuma",
     "content": "Tartalomtípus",
     "language": "Nyelv",
-    "topic": "Téma"
+    "topic": "Téma",
+    "tags": "Saját címkék"
   },
   "show": {
     "unwatched": "Nem nézett",

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

@@ -0,0 +1,12 @@
+{
+  "title": "Címkék kezelése",
+  "channels": "{{count}} csat.",
+  "onChannels": "Címkézett csatornák",
+  "delete": "Törlés",
+  "deleted": "Címke törölve",
+  "deleteTitle": "Címke törlése",
+  "confirmDelete": "Törlöd a(z) „{{name}}” címkét? Minden csatornáról lekerül, amin rajta van.",
+  "empty": "Még nincs címke — adj hozzá lentebb.",
+  "newPlaceholder": "Új címke neve…",
+  "add": "Hozzáad"
+}

frontend/src/lib/api.ts

@@ -1,4 +1,6 @@
 import { notify } from "./notifications";
+import i18n from "../i18n";
+import { reportError } from "./errorDialog";
 
 export interface Me {
   id: number;
@@ -196,9 +198,14 @@ async function req(url: string, opts: RequestInit = {}): Promise<any> {
     } catch {
       /* no JSON body */
     }
-    // Server faults are worth surfacing; 401/403/404 etc. are handled by callers.
+    // Surface anything the server definitively refused as a self-explanatory dialog the
+    // user must acknowledge: 5xx (a fault) and 400/409/422 (validation/conflict, with the
+    // server's own reason). 401/403/404 are control flow handled by callers (auth, demo
+    // gating, not-found), so they just throw.
     if (r.status >= 500) {
-      notifyErrorThrottled(`Server error ${r.status}`, `${method} ${url}`);
+      reportError(detail || `${i18n.t("errors.server")} (${r.status})`);
+    } else if (r.status === 400 || r.status === 409 || r.status === 422) {
+      reportError(detail);
     }
     throw new HttpError(r.status, detail);
   }
@@ -365,6 +372,7 @@ export const api = {
     req(`/api/facets?${filterParams(f).toString()}`),
   setState: (id: string, status: string) =>
     req(`/api/videos/${id}/state`, { method: "POST", body: JSON.stringify({ status }) }),
+  clearState: (id: string) => req(`/api/videos/${id}/state`, { method: "DELETE" }),
   saveProgress: (id: string, positionSeconds: number, durationSeconds: number) =>
     req(`/api/videos/${id}/progress`, {
       method: "POST",

frontend/src/lib/errorDialog.ts

@@ -0,0 +1,38 @@
+import i18n from "../i18n";
+
+// 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
+// (transient, e.g. connection blips) and from silent handling. Module-level so the non-React
+// api layer can raise it; an <ErrorDialog> mounted at the app root renders the current one.
+export interface AppError {
+  title: string;
+  message: string;
+}
+
+let current: AppError | null = null;
+let listeners: Array<() => void> = [];
+const emit = () => listeners.forEach((l) => l());
+
+export function reportError(message?: string, title?: string): void {
+  current = {
+    title: title || i18n.t("errors.title"),
+    message: message || i18n.t("errors.generic"),
+  };
+  emit();
+}
+
+export function dismissError(): void {
+  current = null;
+  emit();
+}
+
+export function subscribeError(listener: () => void): () => void {
+  listeners.push(listener);
+  return () => {
+    listeners = listeners.filter((l) => l !== listener);
+  };
+}
+
+export function getError(): AppError | null {
+  return current;
+}

frontend/src/lib/sidebarLayout.ts

@@ -4,14 +4,15 @@
 
 // `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.
-export type WidgetId = "date" | "language" | "topic";
+export type WidgetId = "date" | "language" | "topic" | "tags";
 
-export const ALL_WIDGETS: WidgetId[] = ["date", "language", "topic"];
+export const ALL_WIDGETS: WidgetId[] = ["date", "language", "topic", "tags"];
 
 export const WIDGET_TITLES: Record<WidgetId, string> = {
   date: "Upload date",
   language: "Language",
   topic: "Topic",
+  tags: "Tags",
 };
 
 export interface SidebarLayout {