refactor(managers): full About overlay + center the wider channel content (E4 S2 follow-up)

- The About overlay now shows the FULL channel About (description, external links,
  country, language, topics, keywords) — the same content as the detail page's About
  tab, via a new shared ChannelAboutContent component (reused by ChannelPage + AboutCell)
- AboutCell fetches the channel detail ON DEMAND on hover (shared [channel,id] react-query
  cache with the channel page), so the list stays light; the overlay is interactive
  (scrollable + clickable links) via a small hover-bridge, and closes on page scroll/resize
- Center the content: max-w-7xl -> max-w-[96rem] on the channel tables + header, so the
  wider About table stays symmetric with the header (mx-auto handles the responsive centering)
- Topic chips are display-only for now; the future search epic makes them clickable

frontend/src/components/AboutCell.tsx

@@ -1,82 +1,131 @@
 import { useEffect, useLayoutEffect, useRef, useState } from "react";
 import { createPortal } from "react-dom";
+import { useQuery } from "@tanstack/react-query";
+import { api } from "../lib/api";
+import ChannelAboutContent from "./ChannelAbout";
 
 const MARGIN = 8;
-const POP_W = 448; // the overlay's fixed width (px)
+const POP_W = 480; // the overlay's fixed width (px)
 
 /**
- * A channel-description cell: one truncated line in the table, with the full text revealed in a
+ * A channel-description cell: one truncated line in the table, revealing the FULL channel "About"
- * glass hover/focus overlay. The overlay is portalled + fixed-positioned so a table's overflow or
+ * (the same content as the detail page's About tab — description, links, country, language, topics,
- * stacking context can't clip it. Unlike Tooltip this is always on (not gated by the hints toggle)
+ * keywords) in a portalled glass overlay. The detail is fetched ON DEMAND on hover/focus, sharing
- * and much wider, since a channel "About" is a paragraph, not a one-liner. Shared by the
+ * the ["channel", id] react-query cache with the channel page, so the list stays light. The overlay
- * subscribed and discovery channel tables.
+ * is interactive (scrollable, links clickable) via a small hover-bridge; it closes on page scroll
+ * (but not when scrolling inside itself) or resize. Shared by the subscribed + discovery tables.
  */
-export default function AboutCell({ text }: { text: string | null }) {
+export default function AboutCell({ text, channelId }: { text: string | null; channelId: string }) {
-  const desc = (text ?? "").trim();
+  const preview = (text ?? "").trim();
   const ref = useRef<HTMLSpanElement>(null);
   const popRef = useRef<HTMLDivElement>(null);
+  const hideTimer = useRef<ReturnType<typeof setTimeout> | null>(null);
+  const [open, setOpen] = useState(false);
   const [coords, setCoords] = useState<{ left: number; top: number } | null>(null);
 
-  function show() {
+  const { data: ch } = useQuery({
+    queryKey: ["channel", channelId],
+    queryFn: () => api.channelDetail(channelId),
+    enabled: open && !!channelId,
+    staleTime: 5 * 60_000,
+  });
+
+  function place() {
     const el = ref.current;
-    if (!el || !desc) return;
+    if (!el) return;
     const r = el.getBoundingClientRect();
     setCoords({
       left: Math.min(Math.max(r.left, MARGIN), window.innerWidth - POP_W - MARGIN),
       top: r.bottom + 6,
     });
   }
-  function hide() {
+  function show() {
-    setCoords(null);
+    if (hideTimer.current) {
+      clearTimeout(hideTimer.current);
+      hideTimer.current = null;
+    }
+    place();
+    setOpen(true);
+  }
+  // Small grace period so the cursor can travel the gap from the cell to the overlay without it
+  // vanishing — the overlay's own mouseenter cancels it.
+  function scheduleHide() {
+    if (hideTimer.current) clearTimeout(hideTimer.current);
+    hideTimer.current = setTimeout(() => setOpen(false), 160);
+  }
+  function cancelHide() {
+    if (hideTimer.current) {
+      clearTimeout(hideTimer.current);
+      hideTimer.current = null;
+    }
   }
 
-  // While open, any scroll or resize would strand the fixed overlay at a stale anchor — close it.
+  useEffect(
+    () => () => {
+      if (hideTimer.current) clearTimeout(hideTimer.current);
+    },
+    [],
+  );
+
+  // Close on page scroll (the fixed overlay would strand at a stale anchor) or resize — but NOT
+  // when the scroll happens inside the overlay itself (it is scrollable).
   useEffect(() => {
-    if (!coords) return;
+    if (!open) return;
-    const close = () => setCoords(null);
+    const onScroll = (e: Event) => {
-    window.addEventListener("scroll", close, true);
+      if (popRef.current && e.target instanceof Node && popRef.current.contains(e.target)) return;
-    window.addEventListener("resize", close);
+      setOpen(false);
-    return () => {
-      window.removeEventListener("scroll", close, true);
-      window.removeEventListener("resize", close);
     };
-  }, [coords]);
+    const onResize = () => setOpen(false);
+    window.addEventListener("scroll", onScroll, true);
+    window.addEventListener("resize", onResize);
+    return () => {
+      window.removeEventListener("scroll", onScroll, true);
+      window.removeEventListener("resize", onResize);
+    };
+  }, [open]);
 
   // Flip above the anchor if the overlay would run off the bottom of the viewport.
   useLayoutEffect(() => {
     const pop = popRef.current;
     const el = ref.current;
-    if (!coords || !pop || !el) return;
+    if (!open || !coords || !pop || !el) return;
     const r = el.getBoundingClientRect();
     const h = pop.offsetHeight;
     if (r.bottom + 6 + h > window.innerHeight - MARGIN && r.top - 6 - h > MARGIN) {
       const top = r.top - 6 - h;
       if (Math.abs(top - coords.top) > 0.5) setCoords((c) => (c ? { ...c, top } : c));
     }
-  }, [coords]);
+  }, [open, coords, ch]);
 
-  if (!desc) return <span className="text-muted">—</span>;
+  if (!preview) return <span className="text-muted">—</span>;
 
   return (
     <span
       ref={ref}
       onMouseEnter={show}
-      onMouseLeave={hide}
+      onMouseLeave={scheduleHide}
       onFocus={show}
-      onBlur={hide}
+      onBlur={scheduleHide}
       tabIndex={0}
       className="block max-w-[22rem] truncate text-muted cursor-help outline-none"
     >
-      {desc}
+      {preview}
-      {coords &&
+      {open &&
+        coords &&
         createPortal(
           <div
             ref={popRef}
-            role="tooltip"
+            onMouseEnter={cancelHide}
+            onMouseLeave={scheduleHide}
             style={{ position: "fixed", left: coords.left, top: coords.top, width: POP_W }}
-            className="glass pointer-events-none z-tooltip max-h-[24rem] overflow-hidden px-3 py-2 rounded-lg text-xs leading-relaxed text-fg whitespace-pre-wrap break-words animate-[fadeIn_0.12s_ease]"
+            className="glass z-tooltip max-h-[28rem] overflow-y-auto px-3.5 py-3 rounded-lg animate-[fadeIn_0.12s_ease]"
           >
-            {desc}
+            {/* Full About once the detail loads; until then the list's truncated description. */}
+            {ch ? (
+              <ChannelAboutContent ch={ch} />
+            ) : (
+              <p className="text-sm whitespace-pre-wrap break-words leading-relaxed">{preview}</p>
+            )}
           </div>,
           document.body,
         )}

frontend/src/components/ChannelAbout.tsx

@@ -0,0 +1,119 @@
+import { useTranslation } from "react-i18next";
+import { ExternalLink } from "lucide-react";
+import type { ChannelDetail } from "../lib/api";
+
+// --- About-tab metadata helpers (shared by the channel page and the manager's About overlay) ---
+// ISO 3166-1 alpha-2 code → 🇺🇸 regional-indicator flag emoji.
+function countryFlag(code: string): string {
+  if (!/^[A-Za-z]{2}$/.test(code)) return "";
+  return String.fromCodePoint(...[...code.toUpperCase()].map((c) => 0x1f1e6 + c.charCodeAt(0) - 65));
+}
+function displayName(code: string, lang: string, type: "region" | "language"): string {
+  try {
+    return new Intl.DisplayNames([lang], { type }).of(type === "region" ? code.toUpperCase() : code) ?? code;
+  } catch {
+    return code;
+  }
+}
+// YouTube keywords are ONE space-separated string with multi-word tags quoted: gaming "let's play".
+function parseKeywords(s: string): string[] {
+  return (s.match(/"[^"]+"|\S+/g) ?? []).map((k) => k.replace(/^"|"$/g, "")).filter(Boolean);
+}
+// topicCategories are Wikipedia URLs (…/wiki/Music) → a readable label, de-duplicated.
+function topicLabels(urls: string[]): string[] {
+  const seen = new Set<string>();
+  for (const url of urls) {
+    const seg = url.split("/wiki/")[1] ?? url.split("/").pop() ?? url;
+    let label = seg;
+    try {
+      label = decodeURIComponent(seg);
+    } catch {
+      /* keep raw */
+    }
+    label = label.replace(/_/g, " ").trim();
+    if (label) seen.add(label);
+  }
+  return [...seen];
+}
+
+/**
+ * The channel "About" content — description, external links, and the enriched metadata
+ * (country, language, topics, keywords). Shared by the channel detail page's About tab and the
+ * Channel manager's About-column hover overlay, so both show exactly the same thing.
+ */
+export default function ChannelAboutContent({ ch }: { ch: ChannelDetail }) {
+  const { t, i18n } = useTranslation();
+  const topics = ch.topic_categories?.length ? topicLabels(ch.topic_categories) : [];
+  const keywords = ch.keywords ? parseKeywords(ch.keywords) : [];
+  const hasAboutDetails =
+    !!ch.country || !!ch.default_language || topics.length > 0 || keywords.length > 0;
+
+  return (
+    <>
+      {ch.description ? (
+        <p className="text-sm whitespace-pre-wrap break-words leading-relaxed">{ch.description}</p>
+      ) : (
+        <p className="text-sm text-muted">{t("channel.noDescription")}</p>
+      )}
+      {ch.external_links && ch.external_links.length > 0 && (
+        <div className="mt-4 flex flex-wrap gap-2">
+          {ch.external_links.map((l, i) => (
+            <a
+              key={i}
+              href={l.url}
+              target="_blank"
+              rel="noreferrer"
+              className="inline-flex items-center gap-1.5 text-sm text-accent hover:underline"
+            >
+              <ExternalLink className="w-3.5 h-3.5" />
+              {l.title || l.url}
+            </a>
+          ))}
+        </div>
+      )}
+      {hasAboutDetails && (
+        <div className="mt-5 space-y-2.5 text-sm border-t border-border pt-4">
+          {ch.country && (
+            <div className="flex gap-2">
+              <span className="text-muted w-24 shrink-0">{t("channel.country")}</span>
+              <span>
+                {countryFlag(ch.country)} {displayName(ch.country, i18n.language, "region")}
+              </span>
+            </div>
+          )}
+          {ch.default_language && (
+            <div className="flex gap-2">
+              <span className="text-muted w-24 shrink-0">{t("channel.language")}</span>
+              <span>{displayName(ch.default_language, i18n.language, "language")}</span>
+            </div>
+          )}
+          {topics.length > 0 && (
+            <div className="flex gap-2">
+              <span className="text-muted w-24 shrink-0 pt-0.5">{t("channel.topics")}</span>
+              <div className="flex flex-wrap gap-1.5">
+                {/* Future search epic: these topic chips become clickable filters. */}
+                {topics.map((tp) => (
+                  <span key={tp} className="glass-card px-2 py-0.5 rounded-full text-xs">
+                    {tp}
+                  </span>
+                ))}
+              </div>
+            </div>
+          )}
+          {keywords.length > 0 && (
+            <div className="flex gap-2">
+              <span className="text-muted w-24 shrink-0 pt-0.5">{t("channel.keywords")}</span>
+              <div className="flex flex-wrap gap-1.5">
+                {keywords.map((kw, i) => (
+                  <span key={i} className="glass-card px-2 py-0.5 rounded-full text-xs">
+                    {kw}
+                  </span>
+                ))}
+              </div>
+            </div>
+          )}
+        </div>
+      )}
+    </>
+  );
+}

frontend/src/components/ChannelDiscovery.tsx

@@ -99,7 +99,7 @@ export default function ChannelDiscovery({
       key: "about",
       header: t("channels.cols.about"),
       hideInCard: true,
-      render: (c) => <AboutCell text={c.description} />,
+      render: (c) => <AboutCell text={c.description} channelId={c.id} />,
     },
     subsColumn<DiscoveredChannel>(t),
     {
@@ -165,11 +165,11 @@ export default function ChannelDiscovery({
     <>
       {/* Intro + the table controls are fixed chrome; only the table rows scroll (sticky header). */}
       <PageToolbar>
-        <div className="px-4 pt-3 max-w-7xl mx-auto">
+        <div className="px-4 pt-3 max-w-[96rem] mx-auto">
           <p className="text-xs text-muted leading-relaxed">{t("channels.discovery.intro")}</p>
         </div>
       </PageToolbar>
-      <div className="px-4 pb-4 max-w-7xl mx-auto">
+      <div className="px-4 pb-4 max-w-[96rem] mx-auto">
         {query.isLoading ? (
           <div className="text-muted py-8">{t("channels.discovery.loading")}</div>
         ) : (
@@ -180,7 +180,7 @@ export default function ChannelDiscovery({
             persistKey={accountKey(LS.channelDiscoveryTable) ?? undefined}
             controlsPosition="both"
             controlsInBand
-            controlsBandClassName="px-4 max-w-7xl mx-auto"
+            controlsBandClassName="px-4 max-w-[96rem] mx-auto"
             emptyText={t("channels.discovery.empty")}
           />
         )}

frontend/src/components/ChannelPage.tsx

@@ -5,6 +5,7 @@ import { useNavigationActions } from "./NavigationProvider";
 import { ArrowLeft, Ban, Check, ExternalLink, Loader2, Plus, RefreshCw, SlidersHorizontal } from "lucide-react";
 import Avatar from "./Avatar";
 import Feed from "./Feed";
+import ChannelAboutContent from "./ChannelAbout";
 import { PageToolbar, PageToolbarSlot } from "./PageShell";
 import { useFeedFilters } from "./FeedFiltersProvider";
 import { useConfirm } from "./ConfirmProvider";
@@ -14,39 +15,6 @@ import { api, type FeedFilters, type Me } from "../lib/api";
 import type { FeedView } from "../lib/feedView";
 import { channelYouTubeUrl, formatViews } from "../lib/format";
 
-// --- About-tab metadata helpers ---
-// ISO 3166-1 alpha-2 code → 🇺🇸 regional-indicator flag emoji.
-function countryFlag(code: string): string {
-  if (!/^[A-Za-z]{2}$/.test(code)) return "";
-  return String.fromCodePoint(...[...code.toUpperCase()].map((c) => 0x1f1e6 + c.charCodeAt(0) - 65));
-}
-function displayName(code: string, lang: string, type: "region" | "language"): string {
-  try {
-    return new Intl.DisplayNames([lang], { type }).of(type === "region" ? code.toUpperCase() : code) ?? code;
-  } catch {
-    return code;
-  }
-}
-// YouTube keywords are ONE space-separated string with multi-word tags quoted: gaming "let's play".
-function parseKeywords(s: string): string[] {
-  return (s.match(/"[^"]+"|\S+/g) ?? []).map((k) => k.replace(/^"|"$/g, "")).filter(Boolean);
-}
-// topicCategories are Wikipedia URLs (…/wiki/Music) → a readable label, de-duplicated.
-function topicLabels(urls: string[]): string[] {
-  const seen = new Set<string>();
-  for (const url of urls) {
-    const seg = url.split("/wiki/")[1] ?? url.split("/").pop() ?? url;
-    let label = seg;
-    try {
-      label = decodeURIComponent(seg);
-    } catch {
-      /* keep raw */
-    }
-    label = label.replace(/_/g, " ").trim();
-    if (label) seen.add(label);
-  }
-  return [...seen];
-}
 
 // A dedicated channel page: an "About"-style header (banner, avatar, stats, subscribe) over the
 // channel's videos (the catalog filtered to this channel). For an un-subscribed channel it
@@ -209,10 +177,6 @@ export default function ChannelPage({
     ch?.total_view_count != null ? t("channel.totalViews", { formatted: formatViews(ch.total_view_count) }) : null,
     joined ? t("channel.joined", { date: joined }) : null,
   ].filter(Boolean) as string[];
-  const topics = ch?.topic_categories?.length ? topicLabels(ch.topic_categories) : [];
-  const keywords = ch?.keywords ? parseKeywords(ch.keywords) : [];
-  const hasAboutDetails =
-    !!ch?.country || !!ch?.default_language || topics.length > 0 || keywords.length > 0;
   const tabClass = (active: boolean) =>
     active
       ? "pb-2 text-sm font-medium border-b-2 border-fg text-fg"
@@ -422,69 +386,11 @@ export default function ChannelPage({
         </>
       ) : (
         <div className="px-4 sm:px-6 py-4 max-w-3xl">
-          {ch?.description ? (
+          {ch ? (
-            <p className="text-sm whitespace-pre-wrap break-words leading-relaxed">{ch.description}</p>
+            <ChannelAboutContent ch={ch} />
           ) : (
             <p className="text-sm text-muted">{t("channel.noDescription")}</p>
           )}
-          {ch?.external_links && ch.external_links.length > 0 && (
-            <div className="mt-4 flex flex-wrap gap-2">
-              {ch.external_links.map((l, i) => (
-                <a
-                  key={i}
-                  href={l.url}
-                  target="_blank"
-                  rel="noreferrer"
-                  className="inline-flex items-center gap-1.5 text-sm text-accent hover:underline"
-                >
-                  <ExternalLink className="w-3.5 h-3.5" />
-                  {l.title || l.url}
-                </a>
-              ))}
-            </div>
-          )}
-          {hasAboutDetails && (
-            <div className="mt-5 space-y-2.5 text-sm border-t border-border pt-4">
-              {ch?.country && (
-                <div className="flex gap-2">
-                  <span className="text-muted w-24 shrink-0">{t("channel.country")}</span>
-                  <span>
-                    {countryFlag(ch.country)} {displayName(ch.country, i18n.language, "region")}
-                  </span>
-                </div>
-              )}
-              {ch?.default_language && (
-                <div className="flex gap-2">
-                  <span className="text-muted w-24 shrink-0">{t("channel.language")}</span>
-                  <span>{displayName(ch.default_language, i18n.language, "language")}</span>
-                </div>
-              )}
-              {topics.length > 0 && (
-                <div className="flex gap-2">
-                  <span className="text-muted w-24 shrink-0 pt-0.5">{t("channel.topics")}</span>
-                  <div className="flex flex-wrap gap-1.5">
-                    {topics.map((tp) => (
-                      <span key={tp} className="glass-card px-2 py-0.5 rounded-full text-xs">
-                        {tp}
-                      </span>
-                    ))}
-                  </div>
-                </div>
-              )}
-              {keywords.length > 0 && (
-                <div className="flex gap-2">
-                  <span className="text-muted w-24 shrink-0 pt-0.5">{t("channel.keywords")}</span>
-                  <div className="flex flex-wrap gap-1.5">
-                    {keywords.map((kw, i) => (
-                      <span key={i} className="glass-card px-2 py-0.5 rounded-full text-xs">
-                        {kw}
-                      </span>
-                    ))}
-                  </div>
-                </div>
-              )}
-            </div>
-          )}
         </div>
       )}
       </PageToolbarSlot.Provider>

frontend/src/components/Channels.tsx

@@ -306,7 +306,7 @@ export default function Channels() {
       key: "about",
       header: t("channels.cols.about"),
       hideInCard: true,
-      render: (c) => <AboutCell text={c.description} />,
+      render: (c) => <AboutCell text={c.description} channelId={c.id} />,
     },
     {
       key: "stored",
@@ -464,7 +464,7 @@ export default function Channels() {
   );
 
   const tabs = (
-    <div className="px-4 pt-4 max-w-7xl mx-auto flex items-center justify-between gap-4 flex-wrap">
+    <div className="px-4 pt-4 max-w-[96rem] mx-auto flex items-center justify-between gap-4 flex-wrap">
       <div className="flex flex-wrap items-center gap-1.5">
         {(["subscribed", "discovery", "blocked"] as ChannelsView[]).map((v) => (
           <button
@@ -492,7 +492,7 @@ export default function Channels() {
     <PageToolbar>
     {tabs}
     {view === "subscribed" && (
-    <div className="px-4 pt-2 pb-2 max-w-7xl mx-auto">
+    <div className="px-4 pt-2 pb-2 max-w-[96rem] mx-auto">
       {/* Your tags (left) share one row with the two catalog-wide actions (right); the channel-name
           search lives in the shared top SearchBar, tag create/delete in the manager. */}
       <div className="flex items-center justify-between gap-4 flex-wrap">
@@ -555,7 +555,7 @@ export default function Channels() {
       />
     ) : view === "blocked" ? (
       /* Blocked channels — videos from these are hidden everywhere and dropped from live search. */
-      <div className="px-4 pb-4 pt-3 max-w-7xl mx-auto">
+      <div className="px-4 pb-4 pt-3 max-w-[96rem] mx-auto">
         {(blockedQuery.data?.length ?? 0) === 0 ? (
           <p className="text-sm text-muted py-8">{t("channels.blocked.empty")}</p>
         ) : (
@@ -592,7 +592,7 @@ export default function Channels() {
       /* No top padding: the sticky header sits flush at the scroller top so it doesn't shift when
          `position: sticky` engages on the first scroll (the band's controls row above gives the
          visual gap). */
-      <div className="px-4 pb-4 max-w-7xl mx-auto">
+      <div className="px-4 pb-4 max-w-[96rem] mx-auto">
         {/* Channel table — only the rows scroll; the header row is sticky, and the controls row
             (status chips + pager) rides in the fixed band right above it (controlsInBand). */}
         {channelsQuery.isLoading ? (
@@ -606,7 +606,7 @@ export default function Channels() {
             controlsPosition="both"
             controlsLeading={statusChips}
             controlsInBand
-            controlsBandClassName="px-4 max-w-7xl mx-auto"
+            controlsBandClassName="px-4 max-w-[96rem] mx-auto"
             rowClassName={(c) => (c.hidden ? "opacity-60" : "")}
             emptyText={t("channels.empty")}
           />