DEPLOY-01: bump version to 0.3.0, changelog for SAFETY-04 and TEL-01

Fixes the version collision noticed while planning DEPLOY-01: release/1.0
still carried version 0.2.1, identical to what is already running on the
live system, so Home Assistant would not have offered the update at all.

- config.yaml: version 0.2.1 -> 0.3.0 (minor: TEL-01 adds a feature,
  SAFETY-04 changes the control law's internals)
- CHANGELOG.md: 0.3.0 entry for SAFETY-04 and TEL-01, in the existing voice

No code under app/ touched, no option defaults changed. Verified:
meter_source: off, integrator_max_w: 0, target_grid_w: -10 all unchanged.

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

goodwe_controller/CHANGELOG.md

@@ -1,5 +1,41 @@
 # Changelog
 
+## 0.3.0
+
+**SAFETY-04.** The control law's integrator is now an explicit accumulator,
+bounded independently of the output clamp instead of inheriting whatever
+headroom the clamp happened to leave. It also freezes while the inverter is
+not tracking, rather than continuing to wind up against a command nothing is
+acting on. `integrator_max_w` (default `0`) governs the bound; `0` means
+"follow `max_w`", which is the existing behaviour.
+
+Behaviour is unchanged at the defaults - a 4,928-case equivalence sweep
+against the previous control law confirms it decides identically at
+`integrator_max_w: 0`.
+
+**TEL-01.** P1 meter ingestion, so a Belgian P1's two unsigned registers
+(consumption, injection) no longer need a hand-written signed template
+sensor: the subtraction moves into the add-on, done once and tested. Two
+transports, chosen with the new `meter_source` option: `ha_dsmr` subscribes
+to the DSMR integration over the HA WebSocket, `mqtt_p1` reads a topic.
+Defaults to `off`, which keeps the existing `meter_entity` path untouched -
+nothing changes for an install that does not opt in.
+
+Enabling it publishes `sensor.p1_sample_age_s`: seconds since the newest
+accepted telegram, recomputed against the clock and republished roughly once
+a second rather than only when a telegram lands. That is deliberate - Home
+Assistant only pushes a state on change, so a meter sitting at a genuinely
+constant reading would otherwise look identical to a dead one. Watching the
+age instead means a frozen meter shows a climbing age, not a flat line. The
+firmware watchdog subscribes to this exact entity id.
+
+Known limits, both already in DOCS.md: on `mqtt_p1`, a bridge stuck
+republishing its last telegram still "arrives", so the age cannot detect
+that particular failure - prefer `ha_dsmr` where both are available. And a
+dead P1 meter takes 45 s to reach 0 W commanded (30 s for `meter_max_age_s`
+to call the reading stale, then 15 s of `stale_input_s` on top), which is
+`meter_max_age_s` and `stale_input_s` stacking, not either one alone.
+
 ## 0.2.1
 
 `target_grid_w` (default -10 W): what the meter should rest at. The deadband

goodwe_controller/config.yaml

@@ -1,5 +1,5 @@
 name: GoodWe RS485 Controller
-version: "0.2.1"
+version: "0.3.0"
 slug: goodwe_controller
 description: >-
   Drives a GoodWe ES/BP battery inverter over RS485 by emulating its smart