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

res/vcpkg/ffmpeg/0001-create-lib-libraries.patch

@@ -0,0 +1,27 @@
+diff --git a/configure b/configure
+index 1f0b9497cb..3243e23021 100644
+--- a/configure
++++ b/configure
+@@ -5697,17 +5697,19 @@ case $target_os in
+         ;;
+     win32|win64)
+         disable symver
+-        if enabled shared; then
++#        if enabled shared; then
+             # Link to the import library instead of the normal static library
+             # for shared libs.
+             LD_LIB='%.lib'
+             # Cannot build both shared and static libs with MSVC or icl.
+-            disable static
+-        fi
++#            disable static
++#        fi
+         ! enabled small && test_cmd $windres --version && enable gnu_windres
+         enabled x86_32 && check_ldflags -LARGEADDRESSAWARE
+         add_cppflags -DWIN32_LEAN_AND_MEAN
+         shlibdir_default="$bindir_default"
++        LIBPREF=""
++        LIBSUF=".lib"
+         SLIBPREF=""
+         SLIBSUF=".dll"
+         SLIBNAME_WITH_VERSION='$(SLIBPREF)$(FULLNAME)-$(LIBVERSION)$(SLIBSUF)'