refactor(player): E.12 — extract skip-to-1★ helper (#575)

`applySkipStarOnManualNext` — the helper that records a manual `next()`
into the per-track skip counter and auto-rates the track 1★ once the
configured threshold crosses — moves into `src/store/skipStarRating.ts`.
File-private with one call site; no caller-side changes outside
playerStore's own import.

10 focused tests pin each early-return branch (manual=false, null
track, threshold not crossed, recordSkipStarManualAdvance returning
null, already-rated via override / queue / passed-track) plus the
happy path that calls setRating(1) + the state update for the queue,
currentTrack, and override map. Promise rejections are verified to
be swallowed.

playerStore 3291 → 3263 LOC.

src/store/skipStarRating.ts

@@ -0,0 +1,37 @@
+import { setRating } from '../api/subsonic';
+import { useAuthStore } from './authStore';
+import { usePlayerStore, type Track } from './playerStore';
+
+/**
+ * Skip → 1★ behaviour: every user-initiated `next()` on an unrated track
+ * counts in `authStore.skipStarManualSkipCountsByKey` (persisted). Once the
+ * configured threshold is crossed, the track is auto-rated 1★ — both on the
+ * Subsonic server and in local Zustand state (queue + currentTrack + the
+ * override map that QueuePanel reads).
+ *
+ * Natural track end (incl. gapless advance) does NOT count; it clears the
+ * threshold counter elsewhere. Already-rated tracks are skipped silently.
+ */
+export function applySkipStarOnManualNext(skippedTrack: Track | null, manual: boolean): void {
+  if (!manual || !skippedTrack) return;
+  const id = skippedTrack.id;
+  const adv = useAuthStore.getState().recordSkipStarManualAdvance(id);
+  if (!adv?.crossedThreshold) return;
+  const live = usePlayerStore.getState();
+  const fromQueue = live.queue.find(t => t.id === id);
+  const cur =
+    live.userRatingOverrides[id] ??
+    fromQueue?.userRating ??
+    skippedTrack.userRating ??
+    0;
+  if (cur >= 1) return;
+  setRating(id, 1)
+    .then(() => {
+      usePlayerStore.setState(s => ({
+        queue: s.queue.map(t => (t.id === id ? { ...t, userRating: 1 } : t)),
+        currentTrack: s.currentTrack?.id === id ? { ...s.currentTrack, userRating: 1 } : s.currentTrack,
+        userRatingOverrides: { ...s.userRatingOverrides, [id]: 1 },
+      }));
+    })
+    .catch(() => {});
+}