feat(lyrics): add Netease Cloud Music as opt-in fallback source

Netease is queried only when server and LRCLIB both return nothing,
preserving the existing lyrics chain completely. Off by default.

- Rust command `fetch_netease_lyrics` proxies Netease API (CORS bypass)
- `src/api/netease.ts` TypeScript wrapper via invoke
- `authStore.enableNeteaselyrics` toggle (default: false)
- `useLyrics`: Netease fires last in fallback chain when enabled
- Settings toggle in the Lyrics section
- `lyricsSourceNetease` label in LyricsPane
- i18n: all 7 languages (en, de, fr, nl, nb, ru, zh)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/pages/Settings.tsx

@@ -873,6 +873,17 @@ export default function Settings() {
                   <span className="toggle-track" />
                 </label>
               </div>
+              <div className="settings-section-divider" />
+              <div className="settings-toggle-row">
+                <div>
+                  <div style={{ fontWeight: 500 }}>{t('settings.enableNeteaselyrics')}</div>
+                  <div style={{ fontSize: 12, color: 'var(--text-muted)' }}>{t('settings.enableNeteaselyricsDesc')}</div>
+                </div>
+                <label className="toggle-switch" aria-label={t('settings.enableNeteaselyrics')}>
+                  <input type="checkbox" checked={auth.enableNeteaselyrics} onChange={e => auth.setEnableNeteaselyrics(e.target.checked)} />
+                  <span className="toggle-track" />
+                </label>
+              </div>
             </div>
           </section>