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

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

start.bat

@@ -0,0 +1,11 @@
+@echo off
+echo Запуск Party Mix...
+where node >nul 2>nul
+IF %ERRORLEVEL% NEQ 0 (
+    echo Node.js не найден. Скачайте с https://nodejs.org
+    pause
+    exit
+)
+start "" http://localhost:3000
+node server.js
+pause