Release 0.2.2

Bump the manifest to 0.2.2 and add CHANGELOG.md with upgrade, reset and
rollback notes covering all reliability work since 0.2.1. The README
drops its accumulated "Unreleased" sections in favor of the changelog
and gains a Diagnostics section explaining the Status attributes and how
to choose freshness limits. The package check now fails if the manifest
version has no changelog entry. ROADMAP marks the Milestone 0 items now
backed by tests and resets the next-session backlog; AUDIT.md records
this round's findings.

Still observation-only. Tested in the HA Core harness with HA 2025.12.0
and 2026.2.3; not on HAOS.

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

CHANGELOG.md

@@ -0,0 +1,92 @@
+# Changelog
+
+Engineering findings and test evidence behind each change are in [AUDIT.md](AUDIT.md).
+
+## 0.2.2 — 2026-10-26
+
+Reliability release (Milestone 0). Still **observation-only**: the integration never
+calls the relay, the thermostat or any other service. No new options or UI text;
+entity IDs and settings carry over. Tested in a Home Assistant Core test harness
+with HA 2025.12.0 and 2026.2.3; not yet tested on HAOS or with real devices.
+
+### Upgrade notes
+
+- Back up Home Assistant, replace `custom_components/heating_mpc`, restart Core.
+- Saved models load, but coefficients learned by 0.2.1 were fitted with a broken
+  radiator-lag estimate (see Fixed). Either let them re-converge over a few days of
+  heating, or reset the model: disable the integration, delete
+  `/config/.storage/heating_mpc.<entry_id>`, restart Core, enable it again. Deleting
+  the file while the integration runs does not work; it saves the model again.
+  Deleting and re-adding the integration also resets it, but loses the settings.
+- After each HA restart, learning pauses for about 30 minutes
+  (`sample_result: lag_uncertain`) because the radiator state is unknown.
+  Forecasts continue.
+- After a day of running, compare each sensor's `max_age_seconds_24h` in Status
+  with the freshness limits in Configure (see README, "Choosing freshness limits").
+- Rollback: restore the previous folder (or the backup) and restart. 0.2.1 reads
+  models saved by 0.2.2 and ignores the new keys.
+
+### Fixed
+
+- The radiator-lag estimate jumped to fully hot or fully cold at every relay
+  change. In simulation this learned the heating gain about a third too low, and
+  forecasts made just after a boiler cycle started from the wrong state.
+- The learner's covariance grew without limit during long OFF periods (for
+  example a summer), which could destabilize learning when heating resumed and
+  eventually make a restart discard the saved model.
+- Optional weather sources could not be removed in Configure.
+- A finished forecast was discarded, making proposed heat unavailable for five
+  minutes, when only a diagnostic weather sensor or the thermostat's current
+  temperature changed during the calculation.
+- Config entries from 0.1 were not migrated.
+- Forecast entities of removed rooms stayed in the entity registry.
+- Malformed or physically implausible saved models could crash setup or be used.
+- ON/OFF readiness counts included rejected samples and other rooms' history.
+- Polls 4–7 minutes apart, or containing a relay change, were learned as normal
+  5-minute samples.
+- Thermostat targets were read as Celsius on Fahrenheit installations.
+- Invalid room weights or optimizer settings could cause crashes.
+- 30/45-minute horizons reported their end point as a 60-minute forecast.
+
+### Added
+
+- Room and weather report-age limits in setup and Configure (5–1440 minutes,
+  defaults 30 and 120). Stale outdoor sources fall back to the next one; a stale
+  room pauses learning and forecasts until it reports again.
+- A read-only listener on the relay, so all relay changes between polls are
+  timestamped and integrated.
+- Models of rooms removed in Configure are kept (up to 24) and restored if the
+  room is added back.
+- Status attributes: `input_quality` (per-source state and report age, including
+  `max_age_seconds_24h`), `heat_lag`, `heat_lag_uncertainty`, `sample_result`,
+  `retired_room_models`, and per-room accepted ON/OFF counts in `models`.
+- Statuses `invalid_weights` and `inputs_changed`.
+
+### Changed
+
+- Readiness now also requires 30 accepted ON and 30 accepted OFF samples per room.
+- Learning skips intervals with a relay change, an outdoor-source switch or an
+  uncertain lag estimate, and polls not 270–330 seconds apart.
+- `input_quality` and `weather_comparison` are no longer written to the Recorder;
+  they change every poll. Other attributes are still recorded.
+
+### Persisted data
+
+- Model payload `schema_version` 2 (0.2.1 wrote no version). Optional keys:
+  per-room `on_count`/`off_count` and `retired_learners`. Older readers ignore them.
+
+### Development
+
+- Home Assistant Core test harness for HA 2025.12.0 and 2026.2.3, a Gitea Actions
+  matrix over both, package and translation validation, and a static test that
+  fails if actuator service calls are added.
+
+## 0.2.1
+
+- Corrects the manifest classification from `helper` to `service`. Existing config
+  entries move from Helpers to **Settings → Devices & services → Integrations**
+  after replacing the files and restarting Home Assistant Core.
+- Deleting the config entry removes its entities and the learned model
+  (`.storage/heating_mpc.<entry_id>`). The component folder stays until removed
+  manually.
+- MPC behavior otherwise unchanged; read-only / shadow-only.