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

flutter/.metadata

@@ -0,0 +1,36 @@
+# This file tracks properties of this Flutter project.
+# Used by Flutter tool to assess capabilities and perform upgrades etc.
+#
+# This file should be version controlled.
+
+version:
+  revision: ee4e09cce01d6f2d7f4baebd247fde02e5008851
+  channel: stable
+
+project_type: app
+
+# Tracks metadata for the flutter migrate command
+migration:
+  platforms:
+    - platform: root
+      create_revision: ee4e09cce01d6f2d7f4baebd247fde02e5008851
+      base_revision: ee4e09cce01d6f2d7f4baebd247fde02e5008851
+    - platform: linux
+      create_revision: ee4e09cce01d6f2d7f4baebd247fde02e5008851
+      base_revision: ee4e09cce01d6f2d7f4baebd247fde02e5008851
+    - platform: macos
+      create_revision: ee4e09cce01d6f2d7f4baebd247fde02e5008851
+      base_revision: ee4e09cce01d6f2d7f4baebd247fde02e5008851
+    - platform: windows
+      create_revision: ee4e09cce01d6f2d7f4baebd247fde02e5008851
+      base_revision: ee4e09cce01d6f2d7f4baebd247fde02e5008851
+
+  # User provided section
+
+  # List of Local paths (relative to this file) that should be
+  # ignored by the migrate tool.
+  #
+  # Files that are not part of the templates will be ignored by default.
+  unmanaged_files:
+    - 'lib/main.dart'
+    - 'ios/Runner.xcodeproj/project.pbxproj'