Initial commit: party-mix-app with prefetch cache, audio preload optimizations

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/web/src/hooks/usePlayer.ts

@@ -0,0 +1,41 @@
+'use client'
+
+import { useRef, useCallback } from 'react'
+
+export function useAudioEngine() {
+  const audioRef = useRef<HTMLAudioElement | null>(null)
+  const audioCtxRef = useRef<AudioContext | null>(null)
+  const analyserRef = useRef<AnalyserNode | null>(null)
+  const sourceRef = useRef<MediaElementAudioSourceNode | null>(null)
+
+  const initAudioViz = useCallback(() => {
+    const audio = audioRef.current
+    if (!audio || typeof window === 'undefined') return
+    try {
+      if (!audioCtxRef.current) {
+        const AudioCtx = window.AudioContext || (window as unknown as { webkitAudioContext: typeof AudioContext }).webkitAudioContext
+        const ctx = new AudioCtx()
+        audioCtxRef.current = ctx
+        const analyser = ctx.createAnalyser()
+        analyser.fftSize = 64
+        analyser.smoothingTimeConstant = 0.8
+        analyserRef.current = analyser
+      }
+      // One MediaElementAudioSourceNode per audio element — never recreate
+      if (!sourceRef.current) {
+        const source = audioCtxRef.current.createMediaElementSource(audio)
+        sourceRef.current = source
+        source.connect(analyserRef.current!)
+        analyserRef.current!.connect(audioCtxRef.current.destination)
+      }
+    } catch {}
+  }, [])
+
+  const resumeContext = useCallback(() => {
+    if (audioCtxRef.current?.state === 'suspended') {
+      audioCtxRef.current.resume()
+    }
+  }, [])
+
+  return { audioRef, analyserRef, audioCtxRef, initAudioViz, resumeContext }
+}