Release 0.2.3

Bump the manifest to 0.2.3 for the stale-room policy: unusable room
sensors are left out with weights re-normalized, and an opt-in checkbox
keeps a stale sensor's last value for up to 24 hours. 0.2.2 was never
deployed, so the changelog marks it as such and the 0.2.3 notes point
0.2.1 users at both entries. ROADMAP and AUDIT record the decision and
the open control-design questions (minimum weight coverage, outdoor
temperature outages).

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

ROADMAP.md

@@ -10,7 +10,7 @@ Success means predictable comfort, understandable decisions, safe operation and
 
 ## Current baseline — v0.2.1
 
-> **Current release: 0.2.2** — Milestone 0 reliability work on top of this
+> **Current release: 0.2.3** — Milestone 0 reliability work on top of this
 > baseline; see [CHANGELOG.md](CHANGELOG.md). The lists below describe 0.2.1.
 
 **Implemented (experimental):**
@@ -165,12 +165,15 @@ Only after the Milestone 3 gate has been satisfied:
 
 Items 1–3 of the original backlog are done (see AUDIT.md and CHANGELOG.md 0.2.2).
 
-1. **HAOS acceptance of 0.2.2 by the user:** install, restart, options reload, room
-   removal and re-adding, manual heat/off, a missing sensor, uninstall on a
-   disposable entry; confirm Generic Thermostat behavior is unchanged.
-2. Finish Milestone 0: decide the stale-room policy (pause all rooms, as now, or
-   keep learning healthy rooms); committed rollback/migration fixtures; failed-fit
-   counters; lint/type checks; remote CI run.
+1. **HAOS acceptance of 0.2.3 by the user:** install, restart, options reload, room
+   removal and re-adding, manual heat/off, a stale and an unavailable room sensor
+   (with the keep-last-value checkbox off and on), uninstall on a disposable
+   entry; confirm Generic Thermostat behavior is unchanged.
+2. Finish Milestone 0: committed rollback/migration fixtures; failed-fit counters;
+   lint/type checks; remote CI run. Stale-room policy decided in 0.2.3 (leave the
+   room out, or optionally keep its last value for up to 24 hours). Before live
+   control, decide a minimum `weight_coverage` and the outdoor-temperature outage
+   policy, which still pauses.
 3. Milestone 1: record forecasts with their input snapshot and evaluate them
    walk-forward at 15/30/60/120 minutes against persistence, replaying the actual
    relay sequence; then expose trajectories for a dashboard.