Agent Skills: desktop-expert

Compose Multiplatform Desktop patterns for the `desktopApp/` module. Use when working with (1) Desktop-only APIs (Window, WindowState, Tray, MenuBar, Dialog), (2) keyboard shortcuts and menu systems with OS-aware conventions (Cmd vs Ctrl, isMacOS branching), (3) desktop navigation (NavigationRail/sidebar vs Android bottom nav, multi-window), (4) file system integration (file pickers, drag-and-drop, Desktop.getDesktop()), (5) OS-specific behavior on macOS/Windows/Linux, (6) desktop UX principles (keyboard-first, tooltips). Delegates shared composables to compose-expert, build/packaging to gradle-expert, and source-set structure to kotlin-multiplatform.