refactor(settings): remove redundant Animations 3-state setting (#495)

* refactor(settings): remove redundant Animations 3-state setting under Seekbar Style

The `animationMode` setting (Full / Reduced / Static) duplicated work
the perf-flag system and OS-level reduced-motion preference already
covered:

- `perfFlags.disableMarqueeScroll` already kills marquee scrolling on
  demand, replacing what `static` mode used to gate.
- The `data-perf-disable-animations` html-level switch already strips
  every `*` animation, replacing what `static` mode used to do globally.
- `@media (prefers-reduced-motion: reduce)` honours the OS setting for
  every user that asked for it via system preferences.
- The 30 fps cap that `reduced` mode applied to the seekbar wave was
  better served by per-feature perf toggles cucadmuh added later.

Removed:
- `AnimationMode` type, `animationMode` field + setter from auth store.
- Settings UI block (3 buttons + hint text) under Appearance > Seekbar
  Style.
- `animationMode === 'static'` short-circuit in WaveformSeek's rAF
  effect; `isReduced` skip-every-other-frame logic; `static`-checks in
  `drawNow` / `needsDirectDraw`.
- `animationMode !== 'static'` guard and `data-anim-mode` attribute in
  MarqueeText.
- `[data-anim-mode="static"]` and `[data-anim-mode="reduced"]` rules in
  layout.css.
- Seven i18n keys (animationMode + 6 variants) across all eight
  locales.

Migration: the persist layer strips `animationMode` (and the legacy
`reducedAnimations` boolean predecessor) so anyone who had `'reduced'`
or `'static'` selected silently lands on the former `'full'` path on
first launch after upgrade. No user-facing prompt — the missing setting
just stops existing.

cucadmuh's PR #472 (FPS overlay), #476 (preview-freeze main seekbar,
sleep-recovery hooks, card-hover removal) and #486 (interpolation
anchor reset on resume) are all preserved untouched — they live in
separate effects / files and were not driven by `animationMode`.

* docs(changelog): add Removed section for animationMode setting (PR #495)

* docs(changelog): refine animationMode removal rationale (drop prefers-reduced-motion overstatement)

src/components/MarqueeText.tsx

@@ -1,5 +1,4 @@
 import React, { useRef, useState, useEffect, useCallback } from 'react';
-import { useAuthStore } from '../store/authStore';
 import { usePerfProbeFlags } from '../utils/perfFlags';
 
 interface Props {
@@ -13,7 +12,6 @@ export default function MarqueeText({ text, className, style, onClick }: Props)
   const containerRef = useRef<HTMLDivElement>(null);
   const textRef = useRef<HTMLSpanElement>(null);
   const [scrollAmount, setScrollAmount] = useState(0);
-  const animationMode = useAuthStore(s => s.animationMode);
   const perfFlags = usePerfProbeFlags();
 
   const measure = useCallback(() => {
@@ -34,9 +32,7 @@ export default function MarqueeText({ text, className, style, onClick }: Props)
     return () => ro.disconnect();
   }, [text, measure]);
 
-  // In `static` animation mode the marquee never scrolls — overflowing text
-  // is truncated with an ellipsis (handled by CSS via data-anim-mode).
-  const shouldScroll = scrollAmount > 0 && animationMode !== 'static' && !perfFlags.disableMarqueeScroll;
+  const shouldScroll = scrollAmount > 0 && !perfFlags.disableMarqueeScroll;
 
   return (
     <div
@@ -44,7 +40,6 @@ export default function MarqueeText({ text, className, style, onClick }: Props)
       className={`marquee-wrap${className ? ` ${className}` : ''}`}
       style={style}
       onClick={onClick}
-      data-anim-mode={animationMode}
     >
       <span
         ref={textRef}

src/components/WaveformSeek.tsx

@@ -967,14 +967,11 @@ export default function WaveformSeek({ trackId }: Props) {
   const waveformBins = usePlayerStore(s => s.waveformBins);
   const duration     = usePlayerStore(s => s.currentTrack?.duration ?? 0);
   const seekbarStyle = useAuthStore(s => s.seekbarStyle);
-  const animationMode = useAuthStore(s => s.animationMode);
 
   // Ref so the subscription callback (closed over at mount) can read the
   // current style without stale-closure issues.
   const styleRef = useRef(seekbarStyle);
   styleRef.current = seekbarStyle;
-  const animationModeRef = useRef(animationMode);
-  animationModeRef.current = animationMode;
 
   useEffect(() => {
     if (!trackId) {
@@ -1096,10 +1093,8 @@ export default function WaveformSeek({ trackId }: Props) {
         visualProgressRef.current = visualTargetProgressRef.current;
       }
       // Static styles always redraw on progress; animated styles let the rAF
-      // loop drive paints. In `static` animation mode we skip the rAF loop
-      // entirely, so animated styles also need to repaint here on every tick.
-      const drawNow =
-        !ANIMATED_STYLES.has(styleRef.current) || animationModeRef.current === 'static';
+      // loop drive paints.
+      const drawNow = !ANIMATED_STYLES.has(styleRef.current);
       if (drawNow) {
         const canvas = canvasRef.current;
         if (!canvas) return;
@@ -1137,28 +1132,14 @@ export default function WaveformSeek({ trackId }: Props) {
     duration,
   ]);
 
-  // rAF loop — animated styles only, and only in `full`/`reduced` mode.
-  // In `static` mode the loop is skipped entirely; the imperative progress
-  // subscription (~2 Hz audio heartbeat) handles repaints, so the seekbar
-  // updates a couple of times per second with no wave animation.
+  // rAF loop — animated styles only.
   useEffect(() => {
     if (!ANIMATED_STYLES.has(seekbarStyle)) return;
-    if (animationMode === 'static') {
-      // Repaint once on entry so the canvas reflects current progress
-      // without any wave morph and stays put until the next heartbeat.
-      const canvas = canvasRef.current;
-      if (canvas) {
-        animStateRef.current = makeAnimState();
-        drawSeekbar(canvas, seekbarStyle, heightsRef.current, progressRef.current, bufferedRef.current, animStateRef.current);
-      }
-      return;
-    }
     const canvas = canvasRef.current;
     if (!canvas) return;
     animStateRef.current = makeAnimState();
     let rafId: number | null = null;
     let pollId: number | null = null;
-    let skip = false;
     const stop = () => {
       if (rafId !== null) {
         cancelAnimationFrame(rafId);
@@ -1177,22 +1158,13 @@ export default function WaveformSeek({ trackId }: Props) {
         }, 400);
         return;
       }
-      // 30 fps cap in `reduced` mode: skip every other rAF, advance
-      // animation time by a doubled delta so wave speed stays the same.
-      const isReduced = animationModeRef.current === 'reduced';
-      if (isReduced && skip) {
-        skip = false;
-        rafId = requestAnimationFrame(tick);
-        return;
-      }
-      skip = isReduced;
-      animStateRef.current.time += isReduced ? 0.032 : 0.016;
+      animStateRef.current.time += 0.016;
       drawSeekbar(canvas, seekbarStyle, heightsRef.current, progressRef.current, bufferedRef.current, animStateRef.current);
       rafId = requestAnimationFrame(tick);
     };
     tick();
     return () => stop();
-  }, [seekbarStyle, animationMode]);
+  }, [seekbarStyle]);
 
   // Smoothly advance progress between sparse transport ticks.
   // Preview pauses main sink in Rust while UI `isPlaying` may still be true.
@@ -1267,8 +1239,7 @@ export default function WaveformSeek({ trackId }: Props) {
           : currentVisual + delta * smoothing;
         visualProgressRef.current = nextVisualProgress;
         progressRef.current = nextVisualProgress;
-        const needsDirectDraw =
-          !ANIMATED_STYLES.has(styleRef.current) || animationModeRef.current === 'static';
+        const needsDirectDraw = !ANIMATED_STYLES.has(styleRef.current);
         if (needsDirectDraw && now - lastPaintAt >= INTERPOLATION_PAINT_MIN_MS) {
           const canvas = canvasRef.current;
           if (canvas) {