LanMountainDesktop/.trae/specs/air-app-whiteboard/spec.md

Air APP Whiteboard

Goal

Allow the built-in whiteboard desktop components to open a full-screen Air APP that runs in LanMountainDesktop.AirAppHost and reuses the same persisted whiteboard note as the source component instance.

Scope

• Add a toolbar surface-mode button to WhiteboardWidget.
• In component mode, the button opens the whiteboard Air APP through IAirAppLauncherService.
• In Air APP mode, the same button saves the current note and closes the Air APP window.
• DesktopWhiteboard and DesktopBlackboardLandscape share the same mechanism and keep using their component id plus placement id as the note identity.
• LanMountainDesktop.AirAppHost may reference the host assembly to reuse built-in UI controls, but the host app must not reference AirAppHost as a normal assembly dependency.

Out of Scope

• Third-party Air APP SDK declarations.
• Whiteboard feature rewrites or alternate whiteboard persistence.
• Taskbar minimization behavior; v1 closes the Air APP window when the user exits from the bottom toolbar.

Acceptance

• Building the main app also builds and copies LanMountainDesktop.AirAppHost output.
• Clicking the whiteboard toolbar full-screen button launches a separate AirAppHost process.
• Repeated opens of the same whiteboard component instance activate the existing process instead of spawning duplicates.
• Closing and reopening the Air APP keeps the same whiteboard contents.