SAFETY-112 review: grade the waiting flag where hass.py sets it

- a 502 or refused read turns waiting on, the next good read off, and a
  read timeout never (two mutants survived without this)
- the flag changes no write with live readings, not only with 502 ones
- the page script's amber dot and batteries-tab banner for "waiting"
- DECISIONS: about 5 minutes per start stage, not "at most"

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

goodwe_controller/DECISIONS/SAFETY-112-waiting-for-home-assistant.md

@@ -51,8 +51,8 @@ Times are seconds after `docker restart` of Home Assistant:
 
 The first write comes 1.0-4.4 s after `RUNNING`, so the whole wait is the
 proxy's. With a 400 s sleep Core moved on at 300.88 s on its own (bootstrap's
-stage timeout), so one slow integration holds the start for about 5 minutes
-at most. The live start took 414 s.
+stage timeout), so one slow integration holds a start stage for about 5
+minutes. The whole start can take longer: the live one took 414 s.
 
 Before this change the page said "Not ready — Battery level: no usable
 reading", which sends the reader to Developer Tools for an entity that is