* feat(webui): auto-request notification permission on first chat send
The Control UI now asks for notification permission automatically on the first chat message you send (once per browser/origin; web push in browsers, native prompt in the macOS app; denied permission is never re-asked automatically — Settings -> Notifications stays the manual path).
* fix(webui): preserve notification prompt gesture boundary
Restrict the one-shot notification prompt to direct non-command composer sends, invoke browser permission synchronously, and keep Settings documented as the management and recovery path.
* fix(webui): exclude deferred notification sends
Require an actively dispatching browser input event before consuming the notification one-shot, so retained catalog handoffs and other deferred sends cannot suppress the first real composer prompt.
Peter Steinberger