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/lib/desktop/widgets/refresh_wrapper.dart

@@ -0,0 +1,45 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_hbb/common.dart';
+import 'package:flutter_hbb/main.dart';
+import 'package:get/get.dart';
+
+class RefreshWrapper extends StatefulWidget {
+  final Widget Function(BuildContext context) builder;
+
+  const RefreshWrapper({super.key, required this.builder});
+
+  @override
+  State<RefreshWrapper> createState() => RefreshWrapperState();
+
+  static RefreshWrapperState? of(BuildContext context) {
+    final state = context.findAncestorStateOfType<RefreshWrapperState>();
+    if (state == null) {
+      debugPrint(
+          "RefreshWrapperState not exists in this context, perhaps RefreshWrapper is not exists?");
+    }
+    return state;
+  }
+}
+
+class RefreshWrapperState extends State<RefreshWrapper> {
+  @override
+  Widget build(BuildContext context) {
+    return widget.builder(context);
+  }
+
+  rebuild() {
+    debugPrint("=====Global State Rebuild (win-${kWindowId ?? 'main'})=====");
+    if (Get.context != null) {
+      (context as Element).visitChildren(_rebuildElement);
+    }
+    // Synchronize the window theme of the system.
+    updateSystemWindowTheme();
+    setState(() {});
+  }
+
+  /// set root tree dirty to trigger global rebuild
+  void _rebuildElement(Element el) {
+    el.markNeedsBuild();
+    el.visitChildren(_rebuildElement);
+  }
+}