test(lyrics): cover the embedded word-lyrics chain (#1268)

Pins the path from a local file's LRC tag to the word lines the pane renders:
Enhanced LRC yields word lines with clean text, plain LRC yields none so the
pane falls back to line sync. Verified to fail when the hook stops forwarding
word lines from the embedded source.

src/features/lyrics/hooks/useLyrics.embedded.test.ts

@@ -0,0 +1,71 @@
+import { renderHook, waitFor } from '@testing-library/react';
+import { beforeEach, describe, expect, it, vi } from 'vitest';
+import { onInvoke } from '@/test/mocks/tauri';
+import { useAuthStore } from '@/store/authStore';
+import { useOfflineStore } from '@/features/offline';
+import { lyricsCache } from '@/features/lyrics/hooks/useLyrics';
+import { useLyrics } from '@/features/lyrics/hooks/useLyrics';
+import type { Track } from '@/lib/media/trackTypes';
+
+/**
+ * The embedded path reads a local file's tags through Rust and never touches the
+ * server. These tests pin the chain from that LRC string to the word lines the
+ * pane renders — the part `parseEnhancedLrc` unit tests cannot see.
+ */
+
+const ENHANCED_LRC = '[00:12.00]<00:12.00>Hello <00:12.90>world\n[00:14.00]<00:14.00>bye';
+const PLAIN_LRC = '[00:12.00]Hello world\n[00:14.00]bye';
+
+const track = { id: 'track-1', title: 'Song', artist: 'Artist', album: 'Album', duration: 20 } as Track;
+
+function mockLocalFile() {
+  vi.spyOn(useOfflineStore, 'getState').mockReturnValue({
+    getLocalUrl: () => 'psysonic-local://C:/music/song.flac',
+  } as unknown as ReturnType<typeof useOfflineStore.getState>);
+}
+
+beforeEach(() => {
+  lyricsCache.clear();
+  vi.restoreAllMocks();
+  // A source must be enabled or the hook treats lyrics as switched off entirely.
+  useAuthStore.setState({
+    activeServerId: 'srv-a',
+    youLyPlusEnabled: false,
+    lyricsSources: [
+      { id: 'server', enabled: true },
+      { id: 'lrclib', enabled: false },
+      { id: 'netease', enabled: false },
+    ],
+  });
+});
+
+describe('useLyrics — embedded Enhanced LRC', () => {
+  it('turns inline word markers into word lines and keeps the text clean', async () => {
+    mockLocalFile();
+    onInvoke('get_embedded_lyrics', () => ENHANCED_LRC);
+
+    const { result } = renderHook(() => useLyrics(track));
+
+    await waitFor(() => expect(result.current.source).toBe('embedded'));
+
+    expect(result.current.syncedLines?.map(l => l.text)).toEqual(['Hello world', 'bye']);
+    expect(result.current.wordLines?.map(l => l.words.map(w => w.text))).toEqual([
+      ['Hello ', 'world'],
+      ['bye'],
+    ]);
+    // The markers must not survive into anything the pane renders.
+    expect(JSON.stringify(result.current.syncedLines)).not.toContain('<00:');
+    expect(JSON.stringify(result.current.wordLines)).not.toContain('<00:');
+  });
+
+  it('leaves word lines empty for plain LRC so the pane falls back to line sync', async () => {
+    mockLocalFile();
+    onInvoke('get_embedded_lyrics', () => PLAIN_LRC);
+
+    const { result } = renderHook(() => useLyrics(track));
+
+    await waitFor(() => expect(result.current.source).toBe('embedded'));
+    expect(result.current.syncedLines).toHaveLength(2);
+    expect(result.current.wordLines).toBeNull();
+  });
+});