feat(plex): expand shows to episodes so a show-collection's Play-all plays (S4)

A collection's Play-all/Shuffle queue held only playable leaves
(movies/episodes), filtering out shows — so on a show-collection the queue
was empty and Play-all was hidden/dead. Build the queue by expanding each
show member into its episodes (season then episode order), concatenated in
member order; leaves still queue as themselves. Shows are fetched lazily on
click (parallel plexShow fetches), not on page load. Gate Play-all/Shuffle
and the poster on "has any playable member" (leaves OR shows), and disable
them while the queue builds. Scope: option A — no member manual-order
migration. Adds plex.collection.playFailed (HU/EN).

frontend/src/components/PlexCollectionView.tsx

@@ -57,6 +57,9 @@ export default function PlexCollectionView({
   const [name, setName] = useState("");
   const [adding, setAdding] = useState(false);
   const [busy, setBusy] = useState(false);
+  // Building the play queue can await show → episode expansion (see buildQueue); disable Play/Shuffle
+  // meanwhile so a double-tap can't fire two queues.
+  const [queueBusy, setQueueBusy] = useState(false);
 
   const invalidate = () => {
     qc.invalidateQueries({ queryKey: qk.plexCollections() });
@@ -64,8 +67,45 @@ export default function PlexCollectionView({
   };
 
   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);
+  // Movies/episodes are playable leaves that queue as themselves; a show can't queue directly, so
+  // Play-all expands it into its episodes (buildQueue). Either kind means there's something to play —
+  // this is what a show-collection needs: before, `playable` held only leaves, so a show-collection's
+  // Play-all was empty and did nothing.
+  const leafKeys = items.filter((c) => c.type !== "show").map((c) => c.id);
+  const hasShows = items.some((c) => c.type === "show");
+  const canPlay = leafKeys.length > 0 || hasShows;
+
+  // Build the ordered play queue: leaf members as themselves, each show member expanded into its
+  // episodes (season then episode order). Shows are fetched lazily HERE (on Play-all/Shuffle click),
+  // in parallel, but concatenated in member order so the queue follows the grid — not on page load,
+  // which would fetch every show up front for a button that may never be pressed.
+  async function buildQueue(): Promise<string[]> {
+    const perMember = await Promise.all(
+      items.map(async (c) => {
+        if (c.type !== "show") return [c.id];
+        const detail = await qc.fetchQuery({
+          queryKey: qk.plexShow(c.id),
+          queryFn: () => api.plexShow(c.id),
+        });
+        return detail.seasons.flatMap((s) => s.episodes.map((e) => e.id));
+      }),
+    );
+    return perMember.flat();
+  }
+
+  async function playAll(shuffle: boolean) {
+    setQueueBusy(true);
+    try {
+      let queue = await buildQueue();
+      if (shuffle) queue = shuffled(queue);
+      if (queue.length > 0) onPlay(queue[0]!, queue);
+    } catch (e) {
+      notifyActionError(e, t("plex.collection.playFailed"));
+    } finally {
+      setQueueBusy(false);
+    }
+  }
+
   const canEdit = isAdmin && !!d?.can_edit;
   // A plain (non-smart, non-external) collection can be admin-enabled for editing. Shares
   // isIntrinsicReadOnly with the browse tile so the lock/edit affordance can't drift between them.
@@ -171,9 +211,9 @@ export default function PlexCollectionView({
           <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)}
+            posterDisabled={!canPlay || queueBusy}
+            showPlayOverlay={canPlay}
+            onPosterClick={() => canPlay && !queueBusy && playAll(false)}
             customizeMenu={null}
           >
             {renaming ? (
@@ -232,19 +272,18 @@ export default function PlexCollectionView({
             )}
 
             <div className="mt-4 flex flex-wrap gap-2">
-              {playable.length > 0 && (
+              {canPlay && (
                 <>
                   <ActionBtn
                     primary
-                    onClick={() => onPlay(playable[0]!, playable)}
+                    onClick={() => playAll(false)}
+                    disabled={queueBusy}
                     icon={Play}
                     label={t("plex.collection.playAll")}
                   />
                   <ActionBtn
-                    onClick={() => {
-                      const order = shuffled(playable);
-                      onPlay(order[0]!, order);
-                    }}
+                    onClick={() => playAll(true)}
+                    disabled={queueBusy}
                     icon={Shuffle}
                     label={t("plex.collection.shuffle")}
                   />

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

@@ -23,6 +23,7 @@
     "added": "Added",
     "deleteConfirm": "Delete the collection \"{{title}}\"? This removes it from Plex too.",
     "editFailed": "Collection edit failed",
+    "playFailed": "Couldn't build the play queue — try again.",
     "newCollection": "New collection",
     "namePlaceholder": "Collection name",
     "nameTaken": "A collection with this name already exists.",

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

@@ -23,6 +23,7 @@
     "added": "Hozzáadva",
     "deleteConfirm": "Törlöd a(z) „{{title}}” kollekciót? Ez a Plexből is eltávolítja.",
     "editFailed": "A kollekció szerkesztése sikertelen",
+    "playFailed": "Nem sikerült összeállítani a lejátszási sort — próbáld újra.",
     "newCollection": "Új kollekció",
     "namePlaceholder": "Kollekció neve",
     "nameTaken": "Már létezik ilyen nevű kollekció.",