"Add Windows installer and driver training rewards"

windows/start_backend.bat

@@ -2,14 +2,25 @@
 setlocal
 
 for %%I in ("%~dp0..") do set "APP_DIR=%%~fI"
-set "LOG_DIR=%APP_DIR%\logs"
-if not exist "%LOG_DIR%" mkdir "%LOG_DIR%"
+where node.exe >nul 2>&1
+if errorlevel 1 (
+  echo [ERROR] Node.js was not found. Run windows\install.bat first.
+  exit /b 1
+)
 
-start "RC Timing Backend" /min cmd /c "cd /d \"%APP_DIR%\" && npm start >> \"%LOG_DIR%\backend.log\" 2>&1"
+pushd "%APP_DIR%"
+call npm.cmd start
+set "EXIT_CODE=%ERRORLEVEL%"
+popd
+
+if not "%EXIT_CODE%"=="0" (
+  echo [ERROR] Backend start failed.
+  exit /b %EXIT_CODE%
+)
 
 echo [OK] Backend started in background
 
 echo      URL: http://localhost:8081
 
-echo      Log: %LOG_DIR%\backend.log
+echo      Logs: %APP_DIR%\logs\server.out.log
 endlocal