feat(plex): Collection info page — hero, play/shuffle, and write-through editing (B)

Clicking a collection tile now opens a dedicated Collection info page (like the Plex-web
one) instead of just applying it as a filter. New GET /collections/{rk} returns the hero
aggregates (year range, most-restrictive member cert, total runtime) + the members ordered
by release year then title; a new PlexCollectionView renders the hero (art/title/meta/
summary+More) and the member grid, with a Play-all and Shuffle over the playable leaves
(reusing the player's existing queue + auto-advance).

For a non-external, admin-enabled collection the page offers rename / delete / add-title
(a search picker) / remove-item, all through the pre-existing admin endpoints that write
THROUGH to Plex (each edit awaits and re-fetches — no optimism, since a Plex write can 422).
An eligible collection shows "Enable editing" first (the DB editable flag). Read-only ones
(smart / imdb / tmdb / … auto-lists) are marked with a lock on both the info page AND the
browse tile, up front.

New `{ kind: "collection" }` sub-view wired through plexSubUrl (bookmarkable ?v=collection:rk),
PlexBrowse (render branch, Backspace back-nav, tile handler), with a round-trip test.

Verified live: tile→page, hero + chronological members (James Bond 1962→2021, PG-13, 55h),
Play/Shuffle, Enable editing → edit controls + remove-X, the add search (marks already-in
titles "Added"), and the read-only lock on external collections. Real Plex mutations wired
but not executed against the live account.

Gate: tsc/lint/knip/prettier clean, 424 vitest; backend ruff clean, 6 collections tests
(+ a detail-hero/ordering assertion).

backend/app/routes/plex/collections.py

@@ -14,12 +14,29 @@ from app.models import (
     PlexShow,
     User,
 )
+from app.plex import rollup
 from app.plex import sync as plex_sync
+from app.plex.cards import movie_card, show_card
 from app.plex.client import PlexClient, PlexError, PlexNotConfigured
 from app.plex.lookups import by_rating_key
 from app.plex.query import like_escape, runtime_by_key, top_art_keys
 from app.routes.plex._shared import _content_libs
 
+# The most-restrictive → least ordering used to pick a collection's effective content rating from its
+# members (Plex shows one cert on the collection; we don't store it, so derive it).
+_CERT_RANK = {
+    "G": 1, "TV-Y": 1, "TV-Y7": 1, "TV-G": 1,
+    "PG": 2, "TV-PG": 2,
+    "PG-13": 3, "TV-14": 3,
+    "R": 4, "TV-MA": 4,
+    "NC-17": 5,
+}
+
+
+def _collection_cert(certs: list[str | None]) -> str | None:
+    ranked = [(c, _CERT_RANK.get(c, 0)) for c in certs if c]
+    return max(ranked, key=lambda x: x[1])[0] if ranked else None
+
 router = APIRouter(prefix="/api/plex", tags=["plex"])
 
 _STRIP_PROVIDERS = ("imdb", "tmdb", "tvdb", "trakt")
@@ -122,6 +139,50 @@ def collections(
     }
 
 
+@router.get("/collections/{rating_key}")
+def collection_detail(
+    rating_key: str,
+    user: User = Depends(current_user),
+    db: Session = Depends(get_db),
+) -> dict:
+    """One collection's hero data + its members (movies + shows), ordered by release year then title —
+    the Collection info page. Read-only here; edits go through the admin mutation endpoints below."""
+    col = by_rating_key(db, PlexCollection, rating_key)
+    if col is None:
+        raise HTTPException(status_code=404, detail="Unknown collection")
+    movies = db.execute(
+        select(PlexItem)
+        .where(PlexItem.kind == "movie", PlexItem.collection_keys.contains([rating_key]))
+        .order_by(PlexItem.year.asc().nullslast(), func.lower(PlexItem.title))
+    ).scalars().all()
+    shows = db.execute(
+        select(PlexShow)
+        .where(PlexShow.collection_keys.contains([rating_key]))
+        .order_by(PlexShow.year.asc().nullslast(), func.lower(PlexShow.title))
+    ).scalars().all()
+    mstate = rollup.item_state_map(db, user.id, [m.id for m in movies])
+    sstate = rollup.state_map(db, user.id, [s.id for s in shows])
+    # Merge the two type-homogeneous lists into ONE member list ordered by (year, title).
+    tagged = [(m.year, (m.title or "").lower(), "movie", m) for m in movies] + [
+        (s.year, (s.title or "").lower(), "show", s) for s in shows
+    ]
+    tagged.sort(key=lambda t: (t[0] is None, t[0] or 0, t[1]))
+    items = [
+        movie_card(o, mstate.get(o.id)) if kind == "movie" else show_card(o, sstate.get(o.id, "new"))
+        for _, _, kind, o in tagged
+    ]
+    years = [y for y, _, _, _ in tagged if y is not None]
+    certs = [m.content_rating for m in movies] + [s.content_rating for s in shows]
+    return {
+        **_collection_card(col),
+        "content_rating": _collection_cert(certs),
+        "year_min": min(years) if years else None,
+        "year_max": max(years) if years else None,
+        "total_runtime_s": sum(m.duration_s or 0 for m in movies),
+        "items": items,
+    }
+
+
 def _editable_collection_or_403(db: Session, rating_key: str) -> PlexCollection:
     col = by_rating_key(db, PlexCollection, rating_key)
     if col is None:

backend/tests/test_plex_collections_filter.py

@@ -94,6 +94,29 @@ def test_collection_cards_carry_montage_art_and_total_runtime(db, monkeypatch):
     assert card["total_runtime_s"] == 5400  # 3600 + 1800
 
 
+def test_collection_detail_hero_and_ordered_members(db, monkeypatch):
+    # The Collection info page: hero aggregates (year range, most-restrictive cert, total runtime) +
+    # members ordered by release year then title.
+    lib = PlexLibrary(plex_key="1", title="Movies", kind="movie", enabled=True)
+    db.add(lib)
+    db.flush()
+    db.add(PlexCollection(rating_key="A", library_id=lib.id, title="Coll A", summary="S", child_count=2))
+    common = dict(library_id=lib.id, kind="movie", collection_keys=["A"])
+    db.add_all([
+        PlexItem(rating_key="later", title="Later", year=1996, duration_s=3600, content_rating="PG", **common),
+        PlexItem(rating_key="early", title="Early", year=1992, duration_s=1800, content_rating="G", **common),
+    ])
+    user = User(email="cd@example.com")
+    db.add(user)
+    db.commit()
+    d = _get(db, user, monkeypatch, "/api/plex/collections/A").json()
+    assert d["title"] == "Coll A" and d["summary"] == "S"
+    assert d["year_min"] == 1992 and d["year_max"] == 1996
+    assert d["content_rating"] == "PG"  # most restrictive of {G, PG}
+    assert d["total_runtime_s"] == 5400
+    assert [i["id"] for i in d["items"]] == ["early", "later"]  # release-year order
+
+
 def test_show_collection_gets_montage_art_from_shows(db, monkeypatch):
     # A show-library collection must get its montage from PlexShow members (else it renders blank) — the
     # A3 fix that unions movie + show art. Runtime stays 0 (shows have no single duration).

frontend/src/components/PlexBrowse.tsx

@@ -42,6 +42,7 @@ import { PlexInfoView, PlexPersonView, PlexSeasonView, PlexShowView } from "./pl
 // Lazy: the rich player (pulls in hls.js) loads only when something is first played.
 const PlexPlayer = lazy(() => import("./PlexPlayer"));
 const PlexPlaylistView = lazy(() => import("./PlexPlaylistView"));
+const PlexCollectionView = lazy(() => import("./PlexCollectionView"));
 
 // The Plex module's content area: browse/search the mirrored library as poster cards, drill from a
 // show into seasons/episodes. Library scope / watch-state / sort live in the left PlexSidebar; the
@@ -173,6 +174,7 @@ export default function PlexBrowse() {
           "info",
           "person",
           "playlist",
+          "collection",
         ].includes(sub.view.kind)
       ) {
         e.preventDefault();
@@ -341,6 +343,20 @@ export default function PlexBrowse() {
       </Suspense>
     );
   }
+  if (sub.view.kind === "collection") {
+    const cid = sub.view.id;
+    return (
+      <Suspense fallback={<p className="p-8 text-muted text-sm">{t("plex.loading")}</p>}>
+        <PlexCollectionView
+          collectionId={cid}
+          onBack={sub.back}
+          onPlay={(rk, queue) => sub.open({ kind: "player", id: rk, queue })}
+          onOpenCard={onCard}
+          onInfoCard={onInfo}
+        />
+      </Suspense>
+    );
+  }
   if (sub.view.kind === "info") {
     const infoId = sub.view.id;
     return (
@@ -431,11 +447,7 @@ export default function PlexBrowse() {
   if (sub.view.kind === "collections") {
     return (
       <div className="p-4 max-w-[1600px] mx-auto">
-        <PlexCollectionsBrowse
-          onPick={(id, title) =>
-            applyFilter({ collections: [id], collectionTitles: { [id]: title } })
-          }
-        />
+        <PlexCollectionsBrowse onPick={(id) => sub.open({ kind: "collection", id })} />
       </div>
     );
   }

frontend/src/components/PlexCollectionView.tsx

@@ -0,0 +1,417 @@
+import { useState } from "react";
+import { useTranslation } from "react-i18next";
+import { useQuery, useQueryClient } from "@tanstack/react-query";
+import { Play, Shuffle, Pencil, Trash2, Plus, X, Lock, Check, Search } from "lucide-react";
+import { qk } from "../lib/queryKeys";
+import { api, type PlexCard, type PlexCollectionDetail } from "../lib/api";
+import { formatRuntime } from "../lib/format";
+import { notifyActionError } from "../lib/actionErrors";
+import { useDebounced } from "../lib/useDebounced";
+import { useConfirm } from "./ConfirmProvider";
+import { BackBtn, ActionBtn, DetailHero } from "../lib/plexDetailUi";
+import { PlexPosterCard } from "./plexCards";
+import { toggleWatchState } from "../lib/plexWatch";
+import { LoadingState, StateMessage } from "./QueryState";
+
+// The Collection info page (ask B): a hero (art/title/cert/year-range/count/runtime/summary) + the
+// ordered member grid, a Play-all / Shuffle over the playable leaves, and — for a NON-external,
+// admin-enabled collection — rename / delete / add / remove, all write-through to Plex (the mutation
+// endpoints round-trip to Plex, so each edit awaits and re-fetches; no optimism). Read-only ones (smart
+// / imdb / tmdb / … auto-lists) are marked with a lock.
+function shuffled(a: string[]): string[] {
+  const r = [...a];
+  for (let i = r.length - 1; i > 0; i--) {
+    const j = Math.floor(Math.random() * (i + 1));
+    const tmp = r[i]!;
+    r[i] = r[j]!;
+    r[j] = tmp;
+  }
+  return r;
+}
+
+export default function PlexCollectionView({
+  collectionId,
+  onBack,
+  onPlay,
+  onOpenCard,
+  onInfoCard,
+}: {
+  collectionId: string;
+  onBack: () => void;
+  onPlay: (rk: string, queue: string[]) => void;
+  onOpenCard: (card: PlexCard) => void;
+  onInfoCard: (card: PlexCard) => void;
+}) {
+  const { t } = useTranslation();
+  const qc = useQueryClient();
+  const confirm = useConfirm();
+  const isAdmin = qc.getQueryData<{ role?: string }>(qk.me())?.role === "admin";
+  const q = useQuery({
+    queryKey: qk.plexCollections("detail", collectionId),
+    queryFn: () => api.plexCollection(collectionId),
+  });
+  const d = q.data;
+
+  const [expanded, setExpanded] = useState(false);
+  const [renaming, setRenaming] = useState(false);
+  const [name, setName] = useState("");
+  const [adding, setAdding] = useState(false);
+  const [busy, setBusy] = useState(false);
+
+  const invalidate = () => {
+    qc.invalidateQueries({ queryKey: qk.plexCollections() });
+    qc.invalidateQueries({ queryKey: qk.plexLibrary() });
+  };
+
+  const items = d?.items ?? [];
+  // The Play queue is the playable-leaf members (movies/episodes) in order — a show can't queue directly.
+  const playable = items.filter((c) => c.type !== "show").map((c) => c.id);
+  const canEdit = isAdmin && !!d?.can_edit;
+  const canEnableEdit =
+    isAdmin && !d?.can_edit && !d?.editable && !d?.smart && d?.source === "collection";
+  const readOnly = !d?.can_edit && !canEnableEdit; // external / smart auto-list
+
+  const toggleWatched = (card: PlexCard) =>
+    toggleWatchState(card, t, {
+      optimistic: (next) => {
+        qc.setQueryData<PlexCollectionDetail>(qk.plexCollections("detail", collectionId), (old) =>
+          old
+            ? {
+                ...old,
+                items: old.items.map((c) => (c.id === card.id ? { ...c, status: next } : c)),
+              }
+            : old,
+        );
+      },
+      resync: () => qc.invalidateQueries({ queryKey: qk.plexLibrary() }),
+    });
+
+  async function doRename() {
+    const title = name.trim();
+    if (!title || !d || title === d.title) {
+      setRenaming(false);
+      return;
+    }
+    setBusy(true);
+    try {
+      await api.plexRenameCollection(collectionId, title);
+      invalidate();
+      setRenaming(false);
+    } catch (e) {
+      notifyActionError(e, t("plex.collection.editFailed"));
+    } finally {
+      setBusy(false);
+    }
+  }
+
+  async function doDelete() {
+    if (!d) return;
+    if (!(await confirm({ message: t("plex.collection.deleteConfirm", { title: d.title }) })))
+      return;
+    setBusy(true);
+    try {
+      await api.plexDeleteCollection(collectionId);
+      invalidate();
+      onBack();
+    } catch (e) {
+      notifyActionError(e, t("plex.collection.editFailed"));
+      setBusy(false);
+    }
+  }
+
+  async function doRemove(card: PlexCard) {
+    setBusy(true);
+    try {
+      await api.plexCollectionRemoveItem(collectionId, card.id);
+      invalidate();
+    } catch (e) {
+      notifyActionError(e, t("plex.collection.editFailed"));
+    } finally {
+      setBusy(false);
+    }
+  }
+
+  async function enableEdit() {
+    setBusy(true);
+    try {
+      await api.plexSetCollectionEditable(collectionId, true);
+      invalidate();
+    } catch (e) {
+      notifyActionError(e, t("plex.collection.editFailed"));
+    } finally {
+      setBusy(false);
+    }
+  }
+
+  const meta = [
+    d?.year_min != null &&
+      (d.year_max && d.year_max !== d.year_min ? `${d.year_min} — ${d.year_max}` : `${d.year_min}`),
+    d?.content_rating,
+    d && t("plex.browse.items", { count: d.child_count ?? items.length }),
+    formatRuntime(d?.total_runtime_s),
+  ].filter(Boolean) as string[];
+
+  return (
+    <div className="glass-media mx-auto max-w-[1200px] p-4">
+      <BackBtn onBack={onBack} label={t("plex.backToLibrary")} />
+
+      {q.isError && !q.data ? (
+        <StateMessage tone="error" onRetry={() => q.refetch()}>
+          {t("common.loadError")}
+        </StateMessage>
+      ) : q.isLoading || !d ? (
+        <LoadingState label={t("plex.loading")} />
+      ) : (
+        <>
+          <DetailHero
+            thumb={d.thumb ?? `/api/plex/image/${d.id}`}
+            posterTitle={t("plex.play")}
+            posterDisabled={playable.length === 0}
+            showPlayOverlay={playable.length > 0}
+            onPosterClick={() => playable.length > 0 && onPlay(playable[0]!, playable)}
+            customizeMenu={null}
+          >
+            {renaming ? (
+              <input
+                autoFocus
+                value={name}
+                onChange={(e) => setName(e.target.value)}
+                onBlur={doRename}
+                onKeyDown={(e) => {
+                  if (e.key === "Enter") doRename();
+                  if (e.key === "Escape") setRenaming(false);
+                }}
+                aria-label={t("plex.collection.rename")}
+                className="glass-card w-full rounded-lg px-2 py-1 text-2xl font-semibold focus:outline-hidden focus:ring-2 focus:ring-accent/40"
+              />
+            ) : (
+              <div className="flex items-center gap-2">
+                <h1 className="text-2xl font-semibold leading-tight">{d.title}</h1>
+                {readOnly && (
+                  <span
+                    className="inline-flex items-center gap-1 rounded-full bg-surface px-2 py-0.5 text-2xs text-muted"
+                    title={t("plex.collection.readOnly")}
+                  >
+                    <Lock className="h-3 w-3" />
+                    {t("plex.collection.readOnly")}
+                  </span>
+                )}
+              </div>
+            )}
+
+            {meta.length > 0 && (
+              <div className="mt-1 flex flex-wrap items-center gap-x-2 text-sm text-muted">
+                {meta.map((m, i) => (
+                  <span key={i}>
+                    {i > 0 && "· "}
+                    {m}
+                  </span>
+                ))}
+              </div>
+            )}
+
+            {d.summary && (
+              <div className="mt-3">
+                <p
+                  className={`text-sm leading-relaxed text-muted ${expanded ? "" : "line-clamp-3"}`}
+                >
+                  {d.summary}
+                </p>
+                <button
+                  onClick={() => setExpanded((v) => !v)}
+                  className="mt-1 text-xs font-medium text-accent hover:underline"
+                >
+                  {expanded ? t("plex.collection.less") : t("plex.collection.more")}
+                </button>
+              </div>
+            )}
+
+            <div className="mt-4 flex flex-wrap gap-2">
+              {playable.length > 0 && (
+                <>
+                  <ActionBtn
+                    primary
+                    onClick={() => onPlay(playable[0]!, playable)}
+                    icon={Play}
+                    label={t("plex.collection.playAll")}
+                  />
+                  <ActionBtn
+                    onClick={() => {
+                      const order = shuffled(playable);
+                      onPlay(order[0]!, order);
+                    }}
+                    icon={Shuffle}
+                    label={t("plex.collection.shuffle")}
+                  />
+                </>
+              )}
+              {canEdit && (
+                <>
+                  <ActionBtn
+                    onClick={() => {
+                      setName(d.title);
+                      setRenaming(true);
+                    }}
+                    icon={Pencil}
+                    label={t("plex.collection.rename")}
+                  />
+                  <ActionBtn
+                    onClick={() => setAdding((v) => !v)}
+                    icon={Plus}
+                    label={t("plex.collection.addItem")}
+                  />
+                  <ActionBtn
+                    onClick={doDelete}
+                    icon={Trash2}
+                    label={t("plex.collection.delete")}
+                    disabled={busy}
+                  />
+                </>
+              )}
+              {canEnableEdit && (
+                <ActionBtn
+                  onClick={enableEdit}
+                  icon={Check}
+                  label={t("plex.collection.enableEdit")}
+                />
+              )}
+            </div>
+          </DetailHero>
+
+          {adding && canEdit && (
+            <AddItemPanel
+              collectionId={collectionId}
+              scope={items.some((c) => c.type === "show") ? "show" : "movie"}
+              existing={new Set(items.map((c) => c.id))}
+              onAdded={invalidate}
+              onClose={() => setAdding(false)}
+            />
+          )}
+
+          {items.length === 0 ? (
+            <p className="text-muted text-sm">{t("plex.collection.empty")}</p>
+          ) : (
+            <div className="grid grid-cols-3 gap-3 sm:grid-cols-4 md:grid-cols-5 lg:grid-cols-6">
+              {items.map((c) => (
+                <div key={c.id} className="relative">
+                  <PlexPosterCard
+                    card={c}
+                    onOpen={() => onOpenCard(c)}
+                    onInfo={() => onInfoCard(c)}
+                    onToggleWatched={toggleWatched}
+                  />
+                  {canEdit && (
+                    <button
+                      onClick={() => doRemove(c)}
+                      disabled={busy}
+                      title={t("plex.collection.removeItem")}
+                      aria-label={t("plex.collection.removeItem")}
+                      className="glass-card glass-hover absolute right-1.5 top-1.5 z-base grid h-6 w-6 place-items-center rounded-full text-fg disabled:opacity-50"
+                    >
+                      <X className="h-3.5 w-3.5" />
+                    </button>
+                  )}
+                </div>
+              ))}
+            </div>
+          )}
+        </>
+      )}
+    </div>
+  );
+}
+
+// A compact search-and-add panel: search the collection's library, click a result to add it (write-
+// through to Plex). Stays open so several items can be added in a row; already-present items are marked.
+function AddItemPanel({
+  collectionId,
+  scope,
+  existing,
+  onAdded,
+  onClose,
+}: {
+  collectionId: string;
+  scope: string;
+  existing: Set<string>;
+  onAdded: () => void;
+  onClose: () => void;
+}) {
+  const { t } = useTranslation();
+  const [term, setTerm] = useState("");
+  const debounced = useDebounced(term.trim(), 300);
+  const [added, setAdded] = useState<Set<string>>(new Set());
+  const q = useQuery({
+    queryKey: qk.plexLibrary("collection-add", scope, debounced),
+    queryFn: () => api.plexLibrary({ scope, q: debounced, limit: 12 }),
+    enabled: debounced.length > 0,
+  });
+  const results = q.data?.items ?? [];
+
+  async function add(card: PlexCard) {
+    try {
+      await api.plexCollectionAddItem(collectionId, card.id);
+      setAdded((s) => new Set(s).add(card.id));
+      onAdded();
+    } catch (e) {
+      notifyActionError(e, t("plex.collection.editFailed"));
+    }
+  }
+
+  return (
+    <div className="glass-card mb-6 rounded-2xl p-4">
+      <div className="mb-3 flex items-center gap-2">
+        <Search className="h-4 w-4 text-muted" />
+        <input
+          autoFocus
+          value={term}
+          onChange={(e) => setTerm(e.target.value)}
+          placeholder={t("plex.collection.addSearch")}
+          aria-label={t("plex.collection.addSearch")}
+          className="glass-card flex-1 rounded-lg px-3 py-1.5 text-sm focus:outline-hidden focus:ring-2 focus:ring-accent/40"
+        />
+        <button
+          onClick={onClose}
+          aria-label={t("common.close")}
+          className="glass-hover grid h-8 w-8 place-items-center rounded-lg"
+        >
+          <X className="h-4 w-4" />
+        </button>
+      </div>
+      {debounced.length === 0 ? (
+        <p className="text-muted text-sm">{t("plex.collection.addHint")}</p>
+      ) : q.isLoading ? (
+        <LoadingState label={t("plex.loading")} />
+      ) : results.length === 0 ? (
+        <p className="text-muted text-sm">{t("plex.collection.addNoResults")}</p>
+      ) : (
+        <ul className="flex flex-col gap-1">
+          {results.map((c) => {
+            const inColl = existing.has(c.id) || added.has(c.id);
+            return (
+              <li key={c.id} className="flex items-center gap-3">
+                <img
+                  src={c.thumb}
+                  alt=""
+                  className="h-12 w-8 shrink-0 rounded object-cover"
+                  loading="lazy"
+                />
+                <span className="min-w-0 flex-1 truncate text-sm">
+                  {c.title}
+                  {c.year != null && <span className="text-muted"> · {c.year}</span>}
+                </span>
+                <button
+                  onClick={() => add(c)}
+                  disabled={inColl}
+                  className="glass-card glass-hover inline-flex items-center gap-1 rounded-lg px-2.5 py-1 text-xs disabled:opacity-50"
+                >
+                  {inColl ? <Check className="h-3.5 w-3.5" /> : <Plus className="h-3.5 w-3.5" />}
+                  {inColl ? t("plex.collection.added") : t("plex.collection.add")}
+                </button>
+              </li>
+            );
+          })}
+        </ul>
+      )}
+    </div>
+  );
+}

frontend/src/components/plexBrowseLists.tsx

@@ -2,7 +2,7 @@ import { useState } from "react";
 import { useTranslation } from "react-i18next";
 import type { TFunction } from "i18next";
 import { useQuery } from "@tanstack/react-query";
-import { ListMusic } from "lucide-react";
+import { ListMusic, Lock } from "lucide-react";
 import { qk } from "../lib/queryKeys";
 import { api, type PlexCollection } from "../lib/api";
 import { formatRuntime } from "../lib/format";
@@ -20,6 +20,12 @@ function collectionMeta(c: PlexCollection, t: TFunction): string {
   return parts.join(" · ");
 }
 
+// A read-only collection (a smart or external auto-list — imdb/tmdb/…) can never be edited; mark it up
+// front on the tile, mirroring the badge on the info page.
+function isReadOnlyCollection(c: PlexCollection): boolean {
+  return !!c.smart || (!!c.source && c.source !== "collection");
+}
+
 // The Playlist / Collection browse surfaces reached from the header pill (Piece 2): a grid of tiles,
 // each a way INTO that area — a playlist tile opens the playlist view, a collection tile filters the
 // title grid by that collection. Both reuse the existing list endpoints (plexPlaylists / plexCollections
@@ -100,6 +106,14 @@ export function PlexCollectionsBrowse({ onPick }: { onPick: (id: string, title:
               title={c.title}
               art={c.art}
               subtitle={collectionMeta(c, t)}
+              topRight={
+                isReadOnlyCollection(c) ? (
+                  <Lock
+                    className="h-3.5 w-3.5 text-white/80 drop-shadow"
+                    aria-label={t("plex.collection.readOnly")}
+                  />
+                ) : undefined
+              }
               onClick={() => onPick(c.id, c.title)}
               className="h-28"
             />

frontend/src/components/plexSubUrl.test.ts

@@ -13,6 +13,7 @@ describe("PLEX_SUB_URL encode", () => {
     expect(U.encode({ kind: "info", id: "m9" })).toBe("info:m9");
     expect(U.encode({ kind: "person", name: "Jane Doe" })).toBe("person:Jane Doe");
     expect(U.encode({ kind: "playlist", id: 12 })).toBe("playlist:12");
+    expect(U.encode({ kind: "collection", id: "c5" })).toBe("collection:c5");
   });
 
   it("does NOT mirror the root Discover landing or the ephemeral player (encode → null)", () => {
@@ -31,6 +32,7 @@ describe("PLEX_SUB_URL round-trip", () => {
     { kind: "info", id: "m9" },
     { kind: "person", name: "Jane Doe" },
     { kind: "playlist", id: 12 },
+    { kind: "collection", id: "c5" },
   ];
   it.each(cases)("encode→decode is identity for %o", (view) => {
     const raw = U.encode(view);
@@ -60,10 +62,11 @@ describe("PLEX_SUB_URL decode guards", () => {
     expect(U.decode("season:s1:se2")).toEqual({ kind: "season", showId: "s1", seasonId: "se2" });
   });
 
-  it("requires a non-empty arg for show / info / person", () => {
+  it("requires a non-empty arg for show / info / person / collection", () => {
     expect(U.decode("show:")).toBeNull();
     expect(U.decode("info:")).toBeNull();
     expect(U.decode("person:")).toBeNull();
+    expect(U.decode("collection:")).toBeNull();
   });
 
   it("rejects an unknown kind or garbage", () => {

frontend/src/components/plexSubUrl.ts

@@ -14,7 +14,8 @@ export type Sub =
   | { kind: "player"; id: string; queue?: string[] }
   | { kind: "info"; id: string }
   | { kind: "person"; name: string }
-  | { kind: "playlist"; id: number };
+  | { kind: "playlist"; id: number }
+  | { kind: "collection"; id: string }; // the Collection info page (id = collection rating_key)
 
 // Mirror the Plex sub-view to ?v=<kind>:<args> so a show / season / movie-info / person / playlist page
 // — and the flat browse grid — are bookmarkable. Discover is the ROOT landing (E5 S4), so it (and the
@@ -41,6 +42,8 @@ export const PLEX_SUB_URL: SubviewUrl<Sub> = {
         return `person:${v.name}`;
       case "playlist":
         return `playlist:${v.id}`;
+      case "collection":
+        return `collection:${v.id}`;
       default:
         return null; // discover (root) + the ephemeral player are not URL-mirrored
     }
@@ -68,6 +71,8 @@ export const PLEX_SUB_URL: SubviewUrl<Sub> = {
         const id = parsePositiveIntId(arg);
         return id != null ? { kind: "playlist", id } : null;
       }
+      case "collection":
+        return arg ? { kind: "collection", id: arg } : null;
       case "season": {
         const [showId, seasonId] = arg.split(":");
         return showId && seasonId ? { kind: "season", showId, seasonId } : null;

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

@@ -2,6 +2,26 @@
   "navLabel": "Plex",
   "backToFeed": "YouTube feed",
   "backToLibrary": "Back to library",
+  "collection": {
+    "playAll": "Play all",
+    "shuffle": "Shuffle",
+    "rename": "Rename",
+    "addItem": "Add title",
+    "delete": "Delete",
+    "enableEdit": "Enable editing",
+    "removeItem": "Remove from collection",
+    "readOnly": "Read-only",
+    "empty": "This collection has no items.",
+    "more": "More",
+    "less": "Less",
+    "addSearch": "Search titles to add…",
+    "addHint": "Type to search for a title to add.",
+    "addNoResults": "No matches.",
+    "add": "Add",
+    "added": "Added",
+    "deleteConfirm": "Delete the collection \"{{title}}\"? This removes it from Plex too.",
+    "editFailed": "Collection edit failed"
+  },
   "searchPlaceholder": "Search Plex…",
   "searchField": {
     "aria": "Search scope",

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

@@ -2,6 +2,26 @@
   "navLabel": "Plex",
   "backToFeed": "YouTube feed",
   "backToLibrary": "Vissza a könyvtárhoz",
+  "collection": {
+    "playAll": "Összes lejátszása",
+    "shuffle": "Keverés",
+    "rename": "Átnevezés",
+    "addItem": "Cím hozzáadása",
+    "delete": "Törlés",
+    "enableEdit": "Szerkesztés engedélyezése",
+    "removeItem": "Eltávolítás a kollekcióból",
+    "readOnly": "Csak olvasható",
+    "empty": "Ennek a kollekciónak nincsenek elemei.",
+    "more": "Több",
+    "less": "Kevesebb",
+    "addSearch": "Keress címet a hozzáadáshoz…",
+    "addHint": "Gépelj a hozzáadni kívánt cím kereséséhez.",
+    "addNoResults": "Nincs találat.",
+    "add": "Hozzáad",
+    "added": "Hozzáadva",
+    "deleteConfirm": "Törlöd a(z) „{{title}}” kollekciót? Ez a Plexből is eltávolítja.",
+    "editFailed": "A kollekció szerkesztése sikertelen"
+  },
   "searchPlaceholder": "Keresés a Plexben…",
   "searchField": {
     "aria": "Keresési hatókör",

frontend/src/lib/api/plex.ts

@@ -187,6 +187,13 @@ export interface PlexCollection {
   art?: string[]; // up to 2 poster rating_keys for the browse-tile montage (browse union only)
   total_runtime_s?: number; // total runtime of all items, for the tile sub-line (browse union only)
 }
+// The Collection info page: the card fields + hero aggregates + the ordered members.
+export interface PlexCollectionDetail extends PlexCollection {
+  content_rating?: string | null;
+  year_min?: number | null;
+  year_max?: number | null;
+  items: PlexCard[];
+}
 export interface PlexPlaylist {
   id: number;
   title: string;
@@ -417,6 +424,9 @@ export const plexApi = {
     const qs = u.toString();
     return req(`/api/plex/collections${qs ? `?${qs}` : ""}`);
   },
+  // One collection's hero + ordered members (the Collection info page).
+  plexCollection: (rk: string): Promise<PlexCollectionDetail> =>
+    req(`/api/plex/collections/${encodeURIComponent(rk)}`),
   // --- Collection editing (admin only; writes back to Plex) ---
   plexCreateCollection: (
     library: string,