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/de.ts

@@ -925,8 +925,13 @@ export const deTranslation = {
     sidebarLyricsStyleAppleDesc: 'Aktive Zeile oben mit sanfter Animation.',
     seekbarStyle: 'Seekbar-Stil',
     seekbarStyleDesc: 'Aussehen der Wiedergabe-Seekbar auswählen',
-    reducedAnimations: 'Animationen reduzieren',
-    reducedAnimationsDesc: 'Animierte Seekbar-Stile auf 30 fps drosseln, um die GPU-Last auf schwächerer Hardware zu senken. Optisch kaum wahrnehmbar.',
+    animationMode: 'Animationen',
+    animationModeDesc: 'Visuelle Glätte gegen geringere GPU-/CPU-Last auf langsamerer Hardware tauschen.',
+    animationModeFull: 'Voll',
+    animationModeReduced: 'Reduziert',
+    animationModeStatic: 'Statisch',
+    animationModeReducedHint: '30 fps Limit auf der Seekbar-Welle; Titel im Player läuft mit halber Geschwindigkeit.',
+    animationModeStaticHint: 'Keine Wellenanimation; Titel im Player wird abgeschnitten statt gescrollt.',
     seekbarTruewave: 'Echte Wellenform',
     seekbarPseudowave: 'Pseudo-Wellenform',
     seekbarLinedot: 'Linie & Punkt',