SerenaDashboardTrayManager._update_menu() called pystray's Icon.update_menu()
on whatever thread reached it. Four call sites are off the main thread: the
Flask handlers for /register, /update_project and /unregister, and
_alive_check_loop.
pystray does no marshalling. Icon.update_menu() calls the backend directly and
pystray/_darwin.py goes straight to NSStatusItem.setMenu_(), which AppKit
requires on the main thread. On macOS versions that enforce it the tray manager
traps with SIGTRAP inside the request handler, so the agent logs "Failed to
register with tray manager: Remote end closed connection without response" and
the tray icon never becomes usable.
Menu refreshes now go through PyObjCTools.AppHelper.callAfter on Darwin, which
is asynchronous so no Flask handler blocks on the main run loop. Other
platforms call through unchanged. The helper is separate from _update_menu
because _open_dashboard and _run_viewer run on the same Flask threads and will
need it too.
No new dependency: PyObjCTools comes from pyobjc-core, already required on
macOS via pystray -> pyobjc-framework-Quartz -> pyobjc-core.
The crash itself could not be reproduced locally (macOS 26.6.2; the reporter is
on 27.0, everything else matching). Verified instead that the AppKit call moves
from a Flask worker thread to the main thread: NSThread.isMainThread() across
the three HTTP routes reads [False, False] before and [True, True, True] after.
