fix(lofi): replace YT IFrame API with direct iframe embed

The YT Player API silently fails to autoplay in hidden iframes.
Replaced with a direct <iframe> embed with allow='autoplay; encrypted-media'.
- On 'Start Lo-Fi': creates iframe with autoplay=1
- Station change: remounts iframe with new videoId
- Volume: postMessage API to YT iframe (best effort)
- Much simpler, no external script dependency

frontend/src/components/MusicPlayer.tsx

@@ -1,4 +1,4 @@
-import { useState, useRef, useEffect, useCallback } from 'react';
+import { useState, useRef, useEffect } from 'react';
 
 interface Playlist {
   id: string;
@@ -17,90 +17,29 @@ export default function MusicPlayer() {
   const [activeId, setActiveId] = useState<string>('lofi-girl');
   const [volume, setVolume] = useState(0.3);
   const [started, setStarted] = useState(false);
-  const [playing, setPlaying] = useState(false);
-  const playerRef = useRef<any>(null);
-  const volumeRef = useRef(volume);
-  const activeIdRef = useRef(activeId);
-  const readyResolveRef = useRef<(() => void) | null>(null);
+  const iframeRef = useRef<HTMLIFrameElement>(null);
 
-  useEffect(() => { volumeRef.current = volume; }, [volume]);
-  useEffect(() => { activeIdRef.current = activeId; }, [activeId]);
+  const active = LOFI_PLAYLISTS.find((p) => p.id === activeId) ?? LOFI_PLAYLISTS[0];
 
-  // Load YouTube IFrame API and create player
-  const initPlayer = useCallback(() => {
-    const active = LOFI_PLAYLISTS.find((p) => p.id === activeIdRef.current);
-    if (!active || playerRef.current) return;
-
-    const createYT = () => {
-      playerRef.current = new (window as any).YT.Player('kira-youtube-player', {
-        height: '1',
-        width: '1',
-        videoId: active.videoId,
-        playerVars: {
-          autoplay: 1,
-          controls: 0,
-          loop: 1,
-          playlist: active.videoId,
-          enablejsapi: 1,
-          modestbranding: 1,
-          fs: 0,
-          rel: 0,
-        },
-        events: {
-          onReady: (e: any) => {
-            e.target.setVolume(Math.round(volumeRef.current * 100));
-            e.target.playVideo();
-            setPlaying(true);
-          },
-          onStateChange: (e: any) => {
-            // YT.PlayerState.PLAYING = 1, PAUSED = 2, ENDED = 0
-            setPlaying(e.data === 1);
-          },
-          onError: (e: any) => {
-            console.warn('[MusicPlayer] YouTube error:', e.data);
-          },
-        },
-      });
-    };
-
-    if ((window as any).YT?.Player) {
-      createYT();
-    } else {
-      // Load the script
-      const tag = document.createElement('script');
-      tag.src = 'https://www.youtube.com/iframe_api';
-      document.head.appendChild(tag);
-      (window as any).onYouTubeIframeAPIReady = createYT;
-    }
-  }, []);
+  // Sync volume to iframe via YT postMessage API
+  useEffect(() => {
+    if (!started || !iframeRef.current) return;
+    const target = Math.round(volume * 100);
+    // YouTube IFrame postMessage API for volume control
+    iframeRef.current.contentWindow?.postMessage(
+      JSON.stringify({ event: 'command', func: 'setVolume', args: [target] }),
+      '*'
+    );
+  }, [volume, started]);
 
   const handlePlay = () => {
     setStarted(true);
-    initPlayer();
   };
 
   const changeStation = (id: string) => {
     setActiveId(id);
-    if (playerRef.current && (window as any).YT) {
-      const active = LOFI_PLAYLISTS.find((p) => p.id === id);
-      if (active) {
-        try {
-          playerRef.current.loadVideoById(active.videoId);
-          playerRef.current.setVolume(Math.round(volume * 100));
-        } catch {}
-      }
-    }
   };
 
-  // Volume sync
-  useEffect(() => {
-    try {
-      if (playerRef.current?.setVolume) {
-        playerRef.current.setVolume(Math.round(volume * 100));
-      }
-    } catch {}
-  }, [volume]);
-
   return (
     <div className="p-4">
       <div className="flex items-center justify-between mb-3">
@@ -125,7 +64,7 @@ export default function MusicPlayer() {
         {LOFI_PLAYLISTS.map((p) => (
           <button
             key={p.id}
-            onClick={() => started ? changeStation(p.id) : setActiveId(p.id)}
+            onClick={() => changeStation(p.id)}
             className={`flex items-center gap-1.5 px-3 py-1.5 rounded-xl text-xs font-medium transition-all ${
               activeId === p.id && started
                 ? 'bg-kira-lav text-white shadow-md'
@@ -138,8 +77,18 @@ export default function MusicPlayer() {
         ))}
       </div>
 
-      {/* YouTube player: must have real dimensions for the API to work */}
-      <div id="kira-youtube-player" style={{ width: 1, height: 1, opacity: 0, position: 'absolute', pointerEvents: 'none' }} />
+      {/* Hidden YouTube iframe — direct embed, no API */}
+      {started && (
+        <iframe
+          ref={iframeRef}
+          src={`https://www.youtube.com/embed/${active.videoId}?autoplay=1&loop=1&playlist=${active.videoId}&controls=0&modestbranding=1&fs=0&rel=0&enablejsapi=1`}
+          width="1"
+          height="1"
+          allow="autoplay; encrypted-media"
+          style={{ position: 'absolute', opacity: 0, pointerEvents: 'none' }}
+          title="lofi player"
+        />
+      )}
 
       <div className="relative rounded-xl overflow-hidden bg-white/30" style={{ height: 60 }}>
         {!started ? (
@@ -152,8 +101,8 @@ export default function MusicPlayer() {
           </button>
         ) : (
           <div className="w-full h-full flex items-center justify-center text-kira-plum/40 text-xs gap-2">
-            <span className={`w-2 h-2 rounded-full animate-pulse inline-block ${playing ? 'bg-kira-mint' : 'bg-kira-plum/30'}`} />
-            <span>playing {LOFI_PLAYLISTS.find((p) => p.id === activeId)?.name}</span>
+            <span className="w-2 h-2 rounded-full bg-kira-mint animate-pulse inline-block" />
+            <span>playing {active.name}</span>
           </div>
         )}
       </div>