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/patch/0010.disable-loading-DLLs-from-app-dir.patch

@@ -0,0 +1,31 @@
+diff --git a/compat/w32dlfcn.h b/compat/w32dlfcn.h
+index ac20e83..1e83aa6 100644
+--- a/compat/w32dlfcn.h
++++ b/compat/w32dlfcn.h
+@@ -76,6 +76,7 @@ static inline HMODULE win32_dlopen(const char *name)
+         if (!name_w)
+             goto exit;
+         namelen = wcslen(name_w);
++        /*
+         // Try local directory first
+         path = get_module_filename(NULL);
+         if (!path)
+@@ -91,6 +92,7 @@ static inline HMODULE win32_dlopen(const char *name)
+         path = new_path;
+         wcscpy(path + pathlen + 1, name_w);
+         module = LoadLibraryExW(path, NULL, LOAD_WITH_ALTERED_SEARCH_PATH);
++        */
+         if (module == NULL) {
+             // Next try System32 directory
+             pathlen = GetSystemDirectoryW(path, pathsize);
+@@ -131,7 +133,9 @@ exit:
+         return NULL;
+     module = LoadPackagedLibrary(name_w, 0);
+ #else
+-#define LOAD_FLAGS (LOAD_LIBRARY_SEARCH_APPLICATION_DIR | LOAD_LIBRARY_SEARCH_SYSTEM32)
++// #define LOAD_FLAGS (LOAD_LIBRARY_SEARCH_APPLICATION_DIR | LOAD_LIBRARY_SEARCH_SYSTEM32)
++// Don't dynamic-link libraries from the application directory.
++ #define LOAD_FLAGS LOAD_LIBRARY_SEARCH_SYSTEM32
+     /* filename may be be in CP_ACP */
+     if (!name_w)
+         return LoadLibraryExA(name, NULL, LOAD_FLAGS);