Two comments asserted an entity id that has never existed

mqtt.py said the P1 age entity "must be exactly sensor.p1_sample_age_s,
because SAFETY-01's firmware watchdog subscribes to that literal id", and
main.py:340 repeated it. Both are wrong, and wrong in the direction that
disarms a safety layer.

On HA 2026.8 object_id in a discovery payload does not determine entity_id.
HA composes it from the device name plus the entity name, so this one is
sensor.goodwe_p1_sample_age. That is what the firmware subscribes to, that is
what exists on the live system (verified 2026-08-26), and the firmware's own
comment records that sensor.p1_sample_age_s never existed on any HA.

The hazard is not the stale name itself, it is that two shipped artefacts
disagreed about a safety-critical id while sounding certain. A reader who
trusted these comments would have "corrected" the firmware to a name that
resolves to nothing - and the failure is silent, because has_state() simply
stays false forever and the ingest guard never arms. The firmware calls that
out as the shape that FAILS SILENTLY AND LOOKS CORRECT.

The comment now says what actually determines the id, and states plainly that
renaming the device or the entity's friendly name changes the composed id and
disarms the guard. It also cross-references TEL-06, since the guard reads this
sensor's value rather than its arrival and so cannot fire for a dead publisher.

Found in a backlog audit, as the substance behind PKG-02's premise: the real
coupling between firmware and add-on is names, not versions.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Du77usMj8XNKNFZGmUiWDa

goodwe_controller/app/main.py

@@ -337,7 +337,8 @@ class Controller:
             "status": "running" if self.auto else "stopped",
         }
         # ⚠️ ONLY when P1 ingestion is actually running. The ESP32's stale-input
-        # watchdog subscribes to sensor.p1_sample_age_s and forces the layer-1
+        # watchdog subscribes to sensor.goodwe_p1_sample_age - see the entity-id
+        # note in mqtt.py; the composed name is not the object_id - and forces layer-1
         # failsafe once it reaches max_age_s. With meter_source off there is no
         # ingester feeding it, so published_age_s would be time-since-startup
         # climbing without bound - i.e. every existing install would cross the