fix(voice): apply waveform review findings

Three review agents (no regressions found). Applied:
- Keyboard arrow-seek now reads the live media currentTime, not the throttled
  ~500ms state, so rapid presses accumulate instead of dropping steps.
- Scrubbing the waveform (or the fallback seek bar) BEFORE first play now loads
  the media and plays from the clicked position (was a silent no-op).
- Unplayed bars use a dimmed accent (color-mix 32%) instead of a faint surface
  token, for consistent contrast across TDS-dark/light + normal themes.
- Fixed first-bar always-lit off-by-one ((i+1)/len), and added overflow:hidden so
  the strip clips rather than overflows in a very narrow drawer.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/components/message/content/AudioContent.tsx

@@ -62,17 +62,22 @@ function WaveformSeek({
   currentTime,
   duration,
   onSeek,
+  getCurrentTime,
 }: {
   waveform: number[];
   currentTime: number;
   duration: number;
   onSeek: (time: number) => void;
+  /** Reads the live media time (the `currentTime` prop is throttled ~500ms). */
+  getCurrentTime: () => number;
 }) {
   const [lotusTerminal] = useSetting(settingsAtom, 'lotusTerminal');
   const containerRef = useRef<HTMLDivElement>(null);
   const bars = useMemo(() => downsampleWaveform(waveform, WAVEFORM_DISPLAY_BARS), [waveform]);
   const barMax = useMemo(() => Math.max(...bars, 1), [bars]);
   const progress = duration > 0 ? Math.min(1, Math.max(0, currentTime / duration)) : 0;
+  const accent = lotusTerminal ? 'var(--lt-accent-green)' : color.Primary.Main;
+  const unplayedColor = `color-mix(in srgb, ${accent} 32%, transparent)`;
 
   const seekFromClientX = useCallback(
     (clientX: number) => {
@@ -94,12 +99,14 @@ function WaveformSeek({
   };
   const handleKeyDown = (evt: React.KeyboardEvent<HTMLDivElement>) => {
     if (duration <= 0) return;
+    // Base off the LIVE time so rapid presses accumulate (the prop is throttled).
+    const base = getCurrentTime();
     if (evt.key === 'ArrowRight' || evt.key === 'ArrowUp') {
       evt.preventDefault();
-      onSeek(Math.min(duration, currentTime + 5));
+      onSeek(Math.min(duration, base + 5));
     } else if (evt.key === 'ArrowLeft' || evt.key === 'ArrowDown') {
       evt.preventDefault();
-      onSeek(Math.max(0, currentTime - 5));
+      onSeek(Math.max(0, base - 5));
     } else if (evt.key === 'Home') {
       evt.preventDefault();
       onSeek(0);
@@ -132,10 +139,11 @@ function WaveformSeek({
         height: toRem(24),
         cursor: 'pointer',
         touchAction: 'none',
+        overflow: 'hidden',
       }}
     >
       {bars.map((v, i) => {
-        const played = bars.length > 0 && i / bars.length <= progress;
+        const played = bars.length > 0 && (i + 1) / bars.length <= progress;
         return (
           <div
             key={i}
@@ -144,11 +152,7 @@ function WaveformSeek({
               minWidth: toRem(2),
               height: toRem(2 + (v / barMax) * 16),
               borderRadius: toRem(1),
-              background: played
-                ? lotusTerminal
-                  ? 'var(--lt-accent-green)'
-                  : color.Primary.Main
-                : color.SurfaceVariant.ContainerActive,
+              background: played ? accent : unplayedColor,
               transition: 'background 0.1s',
             }}
           />
@@ -196,6 +200,8 @@ export function AudioContent({
   );
 
   const audioRef = useRef<HTMLAudioElement | null>(null);
+  // A seek requested before the media has loaded; applied once metadata arrives.
+  const pendingSeekRef = useRef<number | null>(null);
 
   useEffect(
     () => () => {
@@ -236,6 +242,11 @@ export function AudioContent({
     if (!audio) return undefined;
     const applyRate = () => {
       audio.playbackRate = playbackSpeed;
+      // Apply a seek that was requested before the source loaded.
+      if (pendingSeekRef.current != null && audio.readyState >= 1) {
+        audio.currentTime = pendingSeekRef.current;
+        pendingSeekRef.current = null;
+      }
     };
     // Apply immediately, and re-apply whenever the media element (re)loads a new
     // source — e.g. after async decrypt swaps in the blob URL — since the browser
@@ -265,6 +276,20 @@ export function AudioContent({
     }
   };
 
+  // Seeking before the media has loaded (e.g. clicking the waveform first) loads it
+  // and applies the position once metadata arrives (the <audio> autoPlays).
+  const handleSeek = useCallback(
+    (time: number) => {
+      if (srcState.status === AsyncStatus.Success) {
+        seek(time);
+      } else if (srcState.status !== AsyncStatus.Loading) {
+        pendingSeekRef.current = time;
+        loadSrc();
+      }
+    },
+    [srcState.status, seek, loadSrc],
+  );
+
   const hasWaveform = !!waveform && waveform.length > 0 && duration > 0;
 
   return renderMediaControl({
@@ -273,7 +298,8 @@ export function AudioContent({
         waveform={waveform ?? []}
         currentTime={currentTime}
         duration={duration}
-        onSeek={seek}
+        onSeek={handleSeek}
+        getCurrentTime={() => audioRef.current?.currentTime ?? currentTime}
       />
     ) : (
       <Range
@@ -281,7 +307,7 @@ export function AudioContent({
         min={0}
         max={duration || 1}
         values={[currentTime]}
-        onChange={(values) => seek(values[0])}
+        onChange={(values) => handleSeek(values[0])}
         renderTrack={(params) => (
           <div {...params.props}>
             {params.children}