feat(perf): 3-state animation mode (Full / Reduced / Static) (#441)

* feat(perf): 3-state animation mode (Full / Reduced / Static)

Replaces the boolean `reducedAnimations` toggle with a three-way
`animationMode` setting, suggested by Viktor Petrovich after the
Windows audio fix (PR #426) shipped and confirmed a measurable
GPU drop:

- `full` (default): native frame rate, marquee scrolls normally
- `reduced`: 30 fps cap on the animated seekbar wave; player
  marquee runs at half speed
- `static`: rAF loop disabled; the seekbar repaints from the
  ~2 Hz audio:progress heartbeat. Player title/artist truncate
  with ellipsis instead of scrolling.

Migration in `onRehydrateStorage` maps legacy
`reducedAnimations: true` to `'reduced'`, anything else to
`'full'`. Static is opt-in only.

Settings UI follows the ReplayGain Auto/Track/Album pattern with
a contextual hint that explains what each mode does.

i18n: 5 new keys across 8 locales, 2 legacy keys removed.

* docs(changelog): add #441 3-state animation mode entry

* chore(credits): add #441 to Psychotoxical contributions

src/locales/zh.ts

@@ -907,8 +907,13 @@ export const zhTranslation = {
     sidebarLyricsStyleAppleDesc: '活动行固定在顶部，带有平滑弹簧动画。',
     seekbarStyle: '进度条样式',
     seekbarStyleDesc: '选择播放进度条的外观',
-    reducedAnimations: '减少动画',
-    reducedAnimationsDesc: '将动画进度条样式限制为 30 fps，以降低较慢硬件上的 GPU 占用。视觉差异极小。',
+    animationMode: '动画',
+    animationModeDesc: '在较慢的硬件上以视觉流畅度换取更低的 GPU/CPU 占用。',
+    animationModeFull: '完整',
+    animationModeReduced: '减少',
+    animationModeStatic: '静态',
+    animationModeReducedHint: '进度条波形限制为 30 fps；播放器标题以半速滚动。',
+    animationModeStaticHint: '无波形动画；播放器标题被截断而不滚动。',
     seekbarTruewave: '真实波形',
     seekbarPseudowave: '伪波形',
     seekbarLinedot: '线条与点',