WHY: transitions that happen through the API service's panel route
(e.g. a tap on the PWA) published on the API's SSE stream but never
reached Home Assistant's event bus, so the four blueprints only fired
for completions made through the integration's own services. The
integration now subscribes: NestQuestApiClient.stream_events parses
the GET /api/v1/panel/events frames (typed NestQuestApiError on
non-2xx/transport failure, clean stop on cancellation), a new
NestQuestEventStream consumes it in a background task — firing each
documented event type with its documented payload on hass.bus,
reconnecting forever with a 5s-to-60s bounded backoff, never letting
an exception escape — and setup starts it / unload stops it, so no
task leaks.