fix(player): persist player prefs outside quota-bound queue blob (#958)

* fix(player): persist volume/repeat in dedicated localStorage key

Player prefs were bundled with the full queue blob in psysonic-player; after
thin-state #872 a large queue can exceed the quota and safeStorage silently
drops every write, so volume and repeat mode stopped surviving restarts.
Move them to psysonic_player_prefs, gate main-blob writes until rehydrate,
and sync volume to the Rust engine on startup.

* fix(player): split queue visibility and Last.fm cache from main persist blob

Move isQueueVisible and lastfmLovedCache to dedicated localStorage keys so
they keep saving when psysonic-player hits the quota on large queues. Include
the new keys in settings backup export.

* docs: note player prefs persist fix in CHANGELOG and credits (PR #958)

src/store/playerPrefsStorage.test.ts

@@ -0,0 +1,56 @@
+import { afterEach, beforeEach, describe, expect, it } from 'vitest';
+import {
+  persistPlayerPrefs,
+  readInitialPlayerPrefs,
+} from './playerPrefsStorage';
+
+const PREFS_KEY = 'psysonic_player_prefs';
+const LEGACY_KEY = 'psysonic-player';
+
+beforeEach(() => {
+  window.localStorage.clear();
+});
+
+afterEach(() => {
+  window.localStorage.clear();
+});
+
+describe('readInitialPlayerPrefs', () => {
+  it('defaults when nothing is stored', () => {
+    expect(readInitialPlayerPrefs()).toEqual({ volume: 0.8, repeatMode: 'off' });
+  });
+
+  it('reads the dedicated prefs key', () => {
+    window.localStorage.setItem(PREFS_KEY, JSON.stringify({ volume: 0.42, repeatMode: 'all' }));
+    expect(readInitialPlayerPrefs()).toEqual({ volume: 0.42, repeatMode: 'all' });
+  });
+
+  it('clamps an out-of-range volume', () => {
+    window.localStorage.setItem(PREFS_KEY, JSON.stringify({ volume: 1.5, repeatMode: 'one' }));
+    expect(readInitialPlayerPrefs()).toEqual({ volume: 1, repeatMode: 'one' });
+  });
+
+  it('falls back to the legacy psysonic-player blob when the dedicated key is absent', () => {
+    window.localStorage.setItem(
+      LEGACY_KEY,
+      JSON.stringify({ state: { volume: 0.25, repeatMode: 'one', queueItems: [] } }),
+    );
+    expect(readInitialPlayerPrefs()).toEqual({ volume: 0.25, repeatMode: 'one' });
+  });
+
+  it('prefers the dedicated key over the legacy blob', () => {
+    window.localStorage.setItem(PREFS_KEY, JSON.stringify({ volume: 0.6, repeatMode: 'off' }));
+    window.localStorage.setItem(
+      LEGACY_KEY,
+      JSON.stringify({ state: { volume: 0.1, repeatMode: 'all' } }),
+    );
+    expect(readInitialPlayerPrefs()).toEqual({ volume: 0.6, repeatMode: 'off' });
+  });
+});
+
+describe('persistPlayerPrefs', () => {
+  it('round-trips through readInitialPlayerPrefs', () => {
+    persistPlayerPrefs({ volume: 0.33, repeatMode: 'all' });
+    expect(readInitialPlayerPrefs()).toEqual({ volume: 0.33, repeatMode: 'all' });
+  });
+});