Status Bar Service

Runs in: both worker and view. Tray icons that should stay current when the launcher is closed must be registered and updated from the worker.

Permission required: None.

Every top-level IStatusBarItem an extension registers becomes its own independent menu-bar tray icon. Asyar's own tray icon stays separate.

See status-bar.md for the full interface, rules, platform matrix, and migration notes from the pre-Beta shared-tray model.