TEL-05: read the meter, not Home Assistant's opinion of the meter

A fourth meter_source, `homewizard_local`, polling a HomeWizard P1's own
local API (GET /api/v1/data) instead of watching an HA entity.

The point is the age sensor. sensor.p1_sample_age_s is FW-01's watchdog
input, and on every transport we had it measured "time since the value
CHANGED", not "time since the meter REPORTED". Home Assistant offers
nothing better: a repeated reading emits no state_changed, advances
last_reported on neither serialiser, and state_reported cannot be
subscribed to at all. Measured twice - 70 s of a frozen meter on the
ENV-01 rig, and ten repeated readings against the live house. Our own
capture of this house's meter goes 42.2 s and 97.0 s between changes,
both past the default meter_max_age_s of 30, so the age sensor would
have commanded 0 W on a perfectly healthy meter.

Here every HTTP response is an arrival. The meter answered, now, with
its current reading; whether the number moved is not consulted. Five
identical readings are five arrivals.

Reuses TEL-01's pipeline rather than restructuring it: same split_signed
sign convention as ha_signed, same make_sample, same ingest stamping,
meter_max_age_s, clock-recomputed age, plausibility bounds and the §20
unsigned-decode rejection. A failed or timed-out poll submits nothing,
so it is a missing reading - never 0 W - and does not reset the age.
meter_poll_s (default 5 s, the meter's own rate) is checked against
meter_max_age_s once at startup, like the ha_signed entity ids.

⚠️ An arrival stamp cannot see a FROZEN meter, and no arrival detector
can - one answering 200 OK with a stale number is arriving. The local
API does expose what HA never had (the total_power_*_kwh registers stop
advancing) and the transport tracks it as `unchanged_s`, but it is
deliberately not folded into the age and not thresholded: this
controller regulates grid toward ~0 W, and at a converged -10 W the
export register needs six minutes to move by its 1 Wh resolution while
the power figure legitimately repeats. Thresholding that would rebuild
the false-trip limit cycle at the exact operating point we aim for.

test_p1.py 179 -> 236 checks. Still defaults to off.

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

goodwe_controller/config.yaml

@@ -45,10 +45,21 @@ options:
   # integration's entities over the HA WebSocket; mqtt_p1 reads the topic below;
   # ha_signed reads ONE signed HA entity (+ import / - export), which is what a
   # HomeWizard P1 publishes and what ha_dsmr cannot consume.
+  # homewizard_local skips Home Assistant entirely and polls the meter's own
+  # local API. ⚠️ It is the ONLY mode whose sensor.p1_sample_age_s measures when
+  # the meter REPORTED rather than when the value last CHANGED - HA emits
+  # nothing at all for a repeated reading - so it is the only mode a firmware
+  # watchdog may threshold. See DOCS.md.
   meter_source: "off"
   meter_phases: 1
   meter_max_age_s: 30
   meter_mqtt_topic: ""
+  # homewizard_local only. The meter's own address, `host` or `host:port`.
+  p1_host: ""
+  # homewizard_local only. Seconds between polls. Must be well under
+  # meter_max_age_s - the age is never fresher than this interval - and there is
+  # nothing to gain below the meter's own ~5.0 s update rate (NOTES.md:640).
+  meter_poll_s: 5
   # The two UNSIGNED Belgian registers. The EMS derives net power from them
   # (import - export); do NOT point these at a signed template sensor.
   p1_import_entity: ""
@@ -109,14 +120,16 @@ schema:
   batt_invert: bool
   setpoint_entity: str
 
-  meter_source: list(off|ha_dsmr|mqtt_p1|ha_signed)
+  meter_source: list(off|ha_dsmr|mqtt_p1|ha_signed|homewizard_local)
   # ⚠️ 2 is accepted by this range but is not a real Belgian connection. A
   # telegram whose phase count disagrees is rejected at ingest and logged, so a
   # mis-set 2 shows up immediately as "0 telegrams accepted" rather than as a
   # quietly wrong number.
   meter_phases: int(1,3)
   meter_max_age_s: int(5,300)
+  meter_poll_s: int(1,60)
   meter_mqtt_topic: str?
+  p1_host: str?
   p1_import_entity: str?
   p1_export_entity: str?
   p1_phase_import_entities: