fix start and install bat

windows/restart_backend.bat

@@ -0,0 +1,24 @@
+@echo off
+setlocal
+
+for %%I in ("%~dp0..") do set "APP_DIR=%%~fI"
+where node.exe >nul 2>&1
+if errorlevel 1 (
+  echo [ERROR] Node.js was not found. Run windows\install.bat first.
+  exit /b 1
+)
+
+pushd "%APP_DIR%"
+call npm.cmd restart
+set "EXIT_CODE=%ERRORLEVEL%"
+popd
+
+if not "%EXIT_CODE%"=="0" (
+  echo [ERROR] Backend restart failed.
+  exit /b %EXIT_CODE%
+)
+
+echo [OK] Backend restarted in background
+echo      URL: http://localhost:8081
+echo      Logs: %APP_DIR%\logs\server.out.log
+endlocal