🔧 Fix frontend warnings and add diagnostic tools

Fix:
- Add type: module to package.json to eliminate ES module warning
- Create separate backend/frontend startup scripts
- Add system status check tool

New files:
- check_status.bat: Diagnose system status
- start_backend_only.bat: Start backend separately
- start_frontend_only.bat: Start frontend separately

🚀 Generated with [Claude Code](https://claude.com/claude-code)

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

start_frontend_only.bat

@@ -0,0 +1,34 @@
+@echo off
+title QQuiz Frontend Server
+color 0B
+
+echo.
+echo ========================================
+echo   Starting QQuiz Frontend Server
+echo ========================================
+echo.
+
+cd /d "%~dp0frontend"
+
+if not exist "node_modules" (
+    echo Installing dependencies (first time only)...
+    call npm config set registry https://registry.npmmirror.com
+    call npm install
+)
+
+echo.
+echo ========================================
+echo   Frontend Server Starting...
+echo ========================================
+echo.
+echo Frontend URL: http://localhost:3000
+echo.
+echo Make sure backend is running on port 8000!
+echo.
+echo Press Ctrl+C to stop
+echo ========================================
+echo.
+
+npm start
+
+pause