update flasher

flash_tool/build_web_windows.bat

@@ -0,0 +1,32 @@
+@echo off
+echo === ESP32 Flasher (Web UI) - Windows Build Script ===
+echo.
+
+REM Check if running on Windows
+if not "%OS%"=="Windows_NT" (
+    echo Error: This script is for Windows only.
+    echo Use build_web_macos.sh on macOS.
+    exit /b 1
+)
+
+echo Installing dependencies...
+pip install -r requirements.txt
+
+echo.
+echo Building Windows executable...
+pyinstaller ESP32_WebFlasher_Windows.spec
+
+echo.
+if exist "dist\ESP32_Flasher.exe" (
+    echo Build complete!
+    echo.
+    echo Executable created at: dist\ESP32_Flasher.exe
+    echo.
+    echo The app will open in your default web browser!
+    echo You can now distribute ESP32_Flasher.exe to users.
+) else (
+    echo Build failed - executable not found in dist folder
+    exit /b 1
+)
+
+pause