Add Windows build automation with GitHub Actions

- Add comprehensive GitHub Actions workflow for Windows builds
- Create local and CI-specific batch files for building
- Configure export templates and build optimization
- Update export presets for proper .pck embedding and git plugin exclusion
- Set up automated releases with proper build artifacts

build-windows-ci.bat

@@ -0,0 +1,40 @@
+@echo off
+setlocal
+
+echo Building PNGTuber Plus for Windows (CI Environment)...
+
+rem Create build directory
+if not exist "build\windows" mkdir "build\windows"
+
+rem Templates should already be installed by the GitHub Actions workflow
+set TEMPLATE_DIR=C:\WINDOWS\ServiceProfiles\NetworkService\AppData\Roaming\Godot\export_templates\4.4.1.stable
+echo Checking for export templates at: %TEMPLATE_DIR%
+
+if exist "%TEMPLATE_DIR%" (
+    echo Export templates found.
+    dir "%TEMPLATE_DIR%"
+) else (
+    echo ERROR: Export templates not found at %TEMPLATE_DIR%
+    echo This should have been handled by the GitHub Actions setup step.
+    exit /b 1
+)
+
+rem Build the project
+echo Running Godot export...
+"D:\Godot\Godot_v4.4.1-stable_win64.exe" --headless --export-release "Windows Desktop" "build\windows\PNGTuber-Plus.exe"
+
+if %ERRORLEVEL% EQU 0 (
+    echo.
+    echo Build completed successfully!
+    echo Output: build\windows\PNGTuber-Plus.exe
+    if exist "build\windows\PNGTuber-Plus.exe" (
+        echo File size: 
+        dir "build\windows\PNGTuber-Plus.exe"
+    )
+    echo.
+) else (
+    echo.
+    echo Build failed with error code %ERRORLEVEL%
+    echo.
+    exit /b %ERRORLEVEL%
+)