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

libs/scrap/src/lib.rs

@@ -0,0 +1,26 @@
+#[cfg(quartz)]
+extern crate block;
+#[macro_use]
+extern crate cfg_if;
+pub use hbb_common::libc;
+#[cfg(dxgi)]
+extern crate winapi;
+
+pub use common::*;
+
+#[cfg(quartz)]
+pub mod quartz;
+
+#[cfg(x11)]
+pub mod x11;
+
+#[cfg(all(x11, feature = "wayland"))]
+pub mod wayland;
+
+#[cfg(dxgi)]
+pub mod dxgi;
+
+#[cfg(target_os = "android")]
+pub mod android;
+
+mod common;