Settings screen: launch at login (own LaunchAgent), start in menu bar
only, Dock/menu-bar visibility applied live by the window host, keeper
notifications (repaired / needs attention, throttled), manual + weekly
update checks against GitHub releases (never auto-downloads), and
maintenance actions (refresh icon cache, open data folder). Saving
refuses to disable both Dock and menu bar access at once.

Two live-validation fixes: the host's settings poll timer never fired
because JXA does not convert a bridged NSString to a SEL (pass the
selector as a plain string), and NSUserNotification banners from the
unbundled window host are silently dropped by macOS — NotifyUser now
posts via AppleScript display notification, which also works from the
headless keeper.

Co-authored-by: Cursor <cursoragent@cursor.com>