fix: reprise position + visualizer speech-like

Resume: savedPositionRef appliqué sur loadedmetadata pour survivre
au remontage audio après échec CORS. Analyser: fftSize 256,
smoothing 0.55. Simulation: rythme syllabique avec consonantes.

frontend/src/components/AudioVisualizer.tsx

@@ -78,13 +78,17 @@ export default function AudioVisualizer({ height = 80 }: AudioVisualizerProps) {
             hts[i] += (target - hts[i]) * 0.22;
           }
         } else {
-          // Simulated — symmetric wave emanating from center
+          // Simulated speech-like: syllabic rhythm ~4/sec at 60fps
+          const syllable = Math.max(0, Math.sin(frame * 0.038)) ** 2;
+          const breathGroup = Math.sin(frame * 0.007) * 0.25 + 0.75;
+          const consonant = Math.random() < 0.025 ? Math.random() * 0.6 : 0;
           for (let i = 0; i < HALF; i++) {
-            const slow = Math.sin(frame * 0.025 + i * 0.38) * 0.5 + 0.5;
-            const fast = Math.sin(frame * 0.08 + i * 1.1) * 0.35 + 0.65;
-            const pulse = Math.sin(frame * 0.012) * 0.2 + 0.8;
-            const target = MAX_AMPLITUDE * slow * fast * pulse;
-            hts[i] += (target - hts[i]) * 0.18;
+            const t = i / (HALF - 1); // 0=center(bass), 1=edge(treble)
+            // bass tracks syllables, treble spikes on consonants
+            const lowEnergy = syllable * breathGroup * (1 - t * 0.5);
+            const highEnergy = (consonant + syllable * 0.3) * (0.3 + t * 0.7);
+            const target = MAX_AMPLITUDE * (lowEnergy * 0.7 + highEnergy * 0.3);
+            hts[i] += (target - hts[i]) * 0.2;
           }
         }
       } else {

frontend/src/context/AudioContext.tsx

@@ -36,6 +36,7 @@ export function AudioProvider({ children }: { children: ReactNode }) {
   const webAudioRef = useRef<AudioContext | null>(null);
   const analyserRef = useRef<AnalyserNode | null>(null);
   const dataArrayRef = useRef<Uint8Array | null>(null);
+  const savedPositionRef = useRef<number | null>(null);
   const [currentEpisode, setCurrentEpisode] = useState<Episode | null>(null);
   const [isPlaying, setIsPlaying] = useState(false);
   const [currentTime, setCurrentTime] = useState(0);
@@ -97,14 +98,21 @@ export function AudioProvider({ children }: { children: ReactNode }) {
     };
   }, [currentEpisode?._id, userId, isPlaying]);
 
-  // Resume at previous position when episode loads
+  // Resume at previous position: store in ref, applied on loadedmetadata
+  // (handles the case where CORS failure remounts the audio element)
   useEffect(() => {
     if (!currentEpisode || !userId) return;
+    savedPositionRef.current = null;
     setIsResuming(true);
     episodeService.getProgress(currentEpisode._id).then(r => {
-      if (r.progress?.position && audioRef.current) {
-        audioRef.current.currentTime = r.progress.position;
-        setCurrentTime(r.progress.position);
+      const pos = r.progress?.position;
+      if (pos && pos > 5) {
+        savedPositionRef.current = pos;
+        if (audioRef.current && audioRef.current.readyState >= 1) {
+          audioRef.current.currentTime = pos;
+          setCurrentTime(pos);
+          savedPositionRef.current = null;
+        }
       }
       setIsResuming(false);
     }).catch(() => setIsResuming(false));
@@ -121,8 +129,8 @@ export function AudioProvider({ children }: { children: ReactNode }) {
       const ctx = new AudioCtx();
       const source = ctx.createMediaElementSource(audioRef.current);
       const analyser = ctx.createAnalyser();
-      analyser.fftSize = 128;
-      analyser.smoothingTimeConstant = 0.8;
+      analyser.fftSize = 256;
+      analyser.smoothingTimeConstant = 0.55;
       source.connect(analyser);
       analyser.connect(ctx.destination);
 
@@ -226,7 +234,15 @@ export function AudioProvider({ children }: { children: ReactNode }) {
           src={currentEpisode.audioUrl}
           crossOrigin={corsMode === 'cors' ? 'anonymous' : undefined}
           onTimeUpdate={() => audioRef.current && setCurrentTime(audioRef.current.currentTime)}
-          onLoadedMetadata={() => audioRef.current && setDuration(audioRef.current.duration)}
+          onLoadedMetadata={() => {
+            if (!audioRef.current) return;
+            setDuration(audioRef.current.duration);
+            if (savedPositionRef.current !== null) {
+              audioRef.current.currentTime = savedPositionRef.current;
+              setCurrentTime(savedPositionRef.current);
+              savedPositionRef.current = null;
+            }
+          }}
           onPlay={() => setIsPlaying(true)}
           onPause={() => setIsPlaying(false)}
           onEnded={() => setIsPlaying(false)}