LanMountainDesktop/.trae/specs/air-app-window-chrome/spec.md

Air APP Window Chrome

Goal

Give Air APPs explicit window chrome modes so title bars, fullscreen windows, borderless windows, tool windows, and future background-only apps are configured by the Air APP host instead of ad hoc component code.

Behavior

• Air APP host resolves an AirAppWindowDescriptor from launch options before creating content.
• Supported chrome modes are Standard, Borderless, FullScreen, Tool, and BackgroundOnly.
• Standard uses the LanMountain custom title bar and normal app-window behavior.
• Borderless hides the custom title bar while keeping a normal app window.
• FullScreen hides the custom title bar, removes rounded shell chrome, and enters fullscreen.
• Tool keeps host-owned chrome but disables resizing and hides the taskbar entry.
• BackgroundOnly is reserved for a later background Air APP lifecycle and is not used by built-in v1 apps.
• Built-in world-clock uses Standard; built-in whiteboard uses FullScreen.

Out of Scope

• Third-party plugin Air APP declarations.
• Replacing Launcher lifecycle IPC.
• Moving title-bar rendering into desktop components.