UX-08 phase 2a: short, plain notifications, and a ratchet for the rest

Every HA notification the add-on raises now has a title of at most 5
everyday words and a one-sentence body; a red alarm may use three so no
action is lost. The texts live in app/messages.py, the rule in STYLE.md,
and the detail that moved out in DOCS.md "Notifications", which each body
links to. No notification_id, trigger or cadence changed.

test_messages.py enforces the rule on every notification, fails any
notification worded outside app/messages.py, and ratchets the kinds not yet
rewritten (rows, banners, refusals, logs, options) through a shrinking
allowlist of 200. Six tests re-pinned from prose to meaning.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LyR88rXETvwhTgx6yHE39p

goodwe_controller/test_delivery.py

@@ -33,6 +33,7 @@ from datetime import datetime, timedelta, timezone
 
 from named_absence import given, present
 
+from app import messages
 from app.control import Tuning
 from app.delivery import (
     DELIVERY_OPTION_DEFAULTS, DELIVERY_SHARE_FRACTION, REASON_CODE,
@@ -1232,7 +1233,7 @@ check("the notification NAMES THE UNIT - in its id, its title and its body - "
 check("...and it says, in the operator's own sentence, that nothing has been "
       "commanded differently. An alarm that let somebody believe the add-on "
       "had handled it would be worse than no alarm",
-      "NOTHING HAS BEEN COMMANDED DIFFERENTLY" in _note[2]["message"])
+      "nothing was changed and control keeps running" in _note[2]["message"])
 print(f"       id={_note[2]['notification_id']!r} title={_note[2]['title']!r}")
 _before_calls = len(_rh2.calls)
 await_again = asyncio.run(_r2.check_not_delivering())