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

export_presets.cfg

@@ -8,7 +8,7 @@ dedicated_server=false
 custom_features=""
 export_filter="all_resources"
 include_filter=""
-exclude_filter=""
+exclude_filter="addons/godot-git-plugin/*"
 export_path="build/windows/PNGTuber-Plus.exe"
 patches=PackedStringArray()
 encryption_include_filters=""