UX-10: the last plain-language leftovers: log lines, two table rows, 'Why: Other', red at 0 s

- test_messages.py part 6: every dynamic part of a WARNING+ line is classified
  as data or as a built text, and every built text is produced by the real
  code and checked. This is the gap the 2d scan had: it counted `%s` as one
  word, so reasons built by loop_clamp_note() and friends were never seen.
- Quoted reasons rewritten to STYLE.md (red-alarm shape, codes kept):
  OUTPUT_CLAMP, METER_FROZEN, CIRCULATING_POWER, STALE_READING, the peak
  guard (codes now PEAK_GUARD*), the migration report, price feed, price
  history and gate reasons. Plurals via messages.times()/count().
- Top table: Price history "96 prices over 24 hours for 26 Sep", Tariff
  "one every 15 minutes or every hour", "not final yet" dropped.
- Levels and noise: per-cycle shadow line DEBUG, shadow on/off INFO,
  aiohttp access log only at log level debug, settings warnings once per
  start, one plain line per Home Assistant outage (hass.Outage).
- INFO jargon and error texts: no "§8.3", ISO times, "banked", "keys ARE",
  "NOT_OBSERVED", "did NOT land", "AND".
- Display bugs: WHY_WINNER covers every winner and safety reason
  (main.why_key(), part 7 finds them in the code); the meter row is amber
  "waiting for the first reading" inside its limit after a start; the
  missing-reading age is counted when the page asks.
- STYLE.md and DECISIONS/UX-08-short-notifications.md (UX-10 section).

No change to safety behaviour, alarm levels, notification ids, triggers,
cadence or the banner cascade. One row colour changes (meter at start),
justified in DECISIONS.

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

goodwe_controller/app/p1.py

@@ -48,6 +48,7 @@ from datetime import datetime, timezone
 import aiohttp
 
 from . import messages
+from .hass import OUTAGE
 
 _S = messages.setting   # a refusal names the setting by its label (UX-08)
 
@@ -524,6 +525,16 @@ WS_URL = "ws://supervisor/core/websocket"
 BAD_STATES = ("unknown", "unavailable", "none", "")
 
 
+async def _receive_json(ws):
+    """The next JSON message. A socket Home Assistant closed (a restart) is a
+    ConnectionResetError, not aiohttp's "Received message 8:1000 is not str"."""
+    msg = await ws.receive()
+    if msg.type is not aiohttp.WSMsgType.TEXT:
+        raise ConnectionResetError(
+            f"Home Assistant closed the connection ({msg.type.name})")
+    return json.loads(msg.data)
+
+
 class HaDsmrSource:
     """Subscribes to state_changed for the configured DSMR entities.
 
@@ -574,8 +585,12 @@ class HaDsmrSource:
                 backoff = 1.0
             except asyncio.CancelledError:
                 raise
+            except (aiohttp.ClientError, ConnectionError) as err:
+                # UX-10: Home Assistant restarting, said once (hass.Outage).
+                OUTAGE.down("websocket", "the meter connection closed", err)
             except Exception as err:  # noqa: BLE001 - any transport fault retries
-                _LOG.warning("P1 HA websocket: %s - reconnecting in %.0fs", err, backoff)
+                _LOG.warning("The meter connection to Home Assistant failed "
+                             "(%s), trying again in %.0f s.", err, backoff)
             finally:
                 self.connected = False
             await asyncio.sleep(backoff)
@@ -583,16 +598,17 @@ class HaDsmrSource:
 
     async def _session_once(self) -> None:
         async with self.session.ws_connect(WS_URL, heartbeat=30) as ws:
-            hello = await ws.receive_json()
+            hello = await _receive_json(ws)
             if hello.get("type") == "auth_required":
                 await ws.send_json({"type": "auth", "access_token": self.token})
-                reply = await ws.receive_json()
+                reply = await _receive_json(ws)
                 if reply.get("type") != "auth_ok":
                     raise RuntimeError(f"auth rejected: {reply.get('message', reply)}")
             await ws.send_json({"id": 1, "type": "subscribe_events",
                                 "event_type": "state_changed"})
             await ws.send_json({"id": 2, "type": "get_states"})
             self.connected = True
+            OUTAGE.up("websocket")
             _LOG.info("P1 ingest: subscribed to %s", ", ".join(sorted(self.ids)))
 
             async for msg in ws:
@@ -618,7 +634,7 @@ class HaDsmrSource:
                     new = data.get("new_state") or {}
                     self._absorb(data.get("entity_id"), new.get("state"))
                     self._schedule()
-            raise RuntimeError("websocket closed")
+            raise ConnectionResetError("Home Assistant closed the connection")
 
     def _absorb(self, entity_id: str | None, state) -> None:
         if not entity_id or entity_id not in self.ids: