Initial commit: RustDesk 1.4.7 macOS desktop port

- Filled empty libs/hbb_common/ submodule (cloned from rustdesk/hbb_common)
- Patched Flutter 3.44 / Dart 3.12 compatibility:
  * flutter/lib/generated_bridge.dart: asTypedList with cast<>, DartPort=Int64
  * flutter/lib/common.dart: DialogTheme->DialogThemeData, TabBarTheme->TabBarThemeData
  * flutter/pubspec.yaml: extended_text 14.0.0->15.0.2, google_fonts override 5.0.0
  * flutter/macos/Runner/Configs/Release.xcconfig: EXCLUDED_ARCHS=x86_64
- Build verified: cargo check + cargo build --features flutter + cargo build --release --features flutter
- Verified flutter build macos --debug and --release both produce working .app
- Verified .dmg installer (27MB arm64) created via hdiutil
- Build deps: Xcode 26.5, CocoaPods 1.16.2, Flutter 3.44, VCPKG arm64-osx

.gitignore

@@ -0,0 +1,66 @@
+/build
+/target
+.vscode
+.idea
+.DS_Store
+.env
+libsciter-gtk.so
+src/ui/inline.rs
+extractor
+__pycache__
+src/version.rs
+*dmg
+*exe
+*tgz
+cert.pfx
+*.bak
+*png
+*svg
+*jpg
+sciter.dll
+**pdb
+src/bridge_generated.rs
+src/bridge_generated.io.rs
+*deb
+rustdesk
+*.cache
+# rustdesk-master2 build outputs
+flutter/build/
+flutter/.dart_tool/
+flutter/.packages
+flutter/.flutter-plugins
+flutter/.flutter-plugins-dependencies
+.cargo/
+target/
+# appimage
+appimage/AppDir
+appimage/*.AppImage
+appimage/appimage-build
+appimage/*.xz
+# flutter
+flutter/linux/build/**
+flutter/linux/cmake-build-debug/**
+# flatpak
+flatpak/.flatpak-builder/**
+flatpak/ccache/**
+flatpak/.flatpak-builder/build/**
+flatpak/.flatpak-builder/shared-modules/**
+flatpak/.flatpak-builder/shared-modules/*.tar.xz
+flatpak/.flatpak-builder/debian-binary
+flatpak/build/**
+flatpak/repo/**
+flatpak/*.flatpak
+# bridge file
+lib/generated_bridge.dart
+# vscode devcontainer
+.gitconfig
+.vscode-server/
+.ssh
+.devcontainer/.*
+# build cache in examples
+examples/**/target/
+# ===
+vcpkg_installed
+flutter/lib/generated_plugin_registrant.dart
+libsciter.dylib
+flutter/web/