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/README.md

@@ -0,0 +1,62 @@
+Derived from https://github.com/quadrupleslap/scrap
+
+# scrap
+
+Scrap records your screen! At least it does if you're on Windows, macOS, or Linux.
+
+## Usage
+
+```toml
+[dependencies]
+scrap = "0.5"
+```
+
+Its API is as simple as it gets!
+
+```rust
+struct Display; /// A screen.
+struct Frame; /// An array of the pixels that were on-screen.
+struct Capturer; /// A recording instance.
+
+impl Capturer {
+    /// Begin recording.
+    pub fn new(display: Display) -> io::Result<Capturer>;
+
+    /// Try to get a frame.
+    /// Returns WouldBlock if it's not ready yet.
+    pub fn frame<'a>(&'a mut self) -> io::Result<Frame<'a>>;
+
+    pub fn width(&self) -> usize;
+    pub fn height(&self) -> usize;
+}
+
+impl Display {
+    /// The primary screen.
+    pub fn primary() -> io::Result<Display>;
+
+    /// All the screens.
+    pub fn all() -> io::Result<Vec<Display>>;
+
+    pub fn width(&self) -> usize;
+    pub fn height(&self) -> usize;
+}
+
+impl<'a> ops::Deref for Frame<'a> {
+    /// A frame is just an array of bytes.
+    type Target = [u8];
+}
+```
+
+## The Frame Format
+
+- The frame format is guaranteed to be **packed BGRA**.
+- The width and height are guaranteed to remain constant.
+- The stride might be greater than the width, and it may also vary between frames.
+
+## System Requirements
+
+OS      | Minimum Requirements
+--------|---------------------
+macOS   | macOS 10.8
+Linux   | XCB + SHM + RandR
+Windows | DirectX 11.1