some improvements

run_device_main.bat

@@ -4,40 +4,45 @@ setlocal
 set "PROJECT_DIR=%~dp0"
 pushd "%PROJECT_DIR%" >nul || (
     echo Failed to switch to project directory: %PROJECT_DIR%
+    pause
     exit /b 1
 )
 
 set "VENV_DIR=.venv"
 set "VENV_PYTHON=%VENV_DIR%\Scripts\python.exe"
-set "VENV_ACTIVATE=%VENV_DIR%\Scripts\activate.bat"
 
-if exist "%VENV_PYTHON%" goto venv_ready
+rem --- If the venv already exists, just run the app (works fully offline) ---
+if exist "%VENV_PYTHON%" goto run
 
-echo Creating virtual environment...
+rem --- First run only: create venv and install dependencies (needs internet) ---
+echo Virtual environment not found. Creating it (internet required, one time only)...
 call :find_python
 if errorlevel 1 goto :error
 
 "%PYTHON_EXE%" %PYTHON_ARGS% -m venv "%VENV_DIR%"
 if errorlevel 1 goto :error
 
-:venv_ready
-
-call "%VENV_ACTIVATE%"
-if errorlevel 1 goto :error
-
 if exist "requirements.txt" (
     echo Installing dependencies...
-    python -m pip install --disable-pip-version-check -r requirements.txt
-    if errorlevel 1 goto :error
+    "%VENV_PYTHON%" -m pip install --disable-pip-version-check -r requirements.txt
+    if errorlevel 1 (
+        echo.
+        echo Failed to install dependencies. Check your internet connection and run again.
+        rem Remove the half-baked venv so the next run retries cleanly.
+        rmdir /s /q "%VENV_DIR%"
+        goto :error
+    )
 ) else (
     echo requirements.txt not found. Skipping dependency installation.
 )
 
+:run
 echo Starting laser_control.gui.main...
-python -m laser_control.gui.main
+"%VENV_PYTHON%" -m laser_control.gui.main
 set "EXIT_CODE=%ERRORLEVEL%"
 
 popd >nul
+if not "%EXIT_CODE%"=="0" pause
 exit /b %EXIT_CODE%
 
 :find_python
@@ -62,4 +67,5 @@ exit /b 1
 set "EXIT_CODE=%ERRORLEVEL%"
 echo Script failed with exit code %EXIT_CODE%.
 popd >nul
+pause
 exit /b %EXIT_CODE%