Document second audit pass

Record findings, evidence, compatibility notes and remaining gaps in
AUDIT.md; add user-facing upgrade notes to README and update test
counts; note progress against Milestone 0 in ROADMAP. No version bump.

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

ROADMAP.md

@@ -70,6 +70,14 @@ remote runner execution remains unverified. Next improve event-based sampling an
 identity/persistence migration tests, then extend the HA version matrix. Only after those reliability checks proceed to Milestone 1's
 recorded forecasts and walk-forward evaluation. Live control remains unauthorized.
 
+A second audit pass (see AUDIT.md) fixed radiator-lag resets at every relay change,
+RLS covariance windup and a restore tolerance that could reset long-running models,
+optional weather sources that could not be cleared in Options, and spurious
+prediction discards. It added `sample_result`/lag diagnostics and a static
+shadow-only tripwire test. Relay transitions between polls are now integrated at
+their timestamp; multiple changes within one poll still need event-based relay
+history before the transition item below can be checked.
+
 ## Milestone 1 — Explainable forecasts and dashboards (target v0.3.0)
 
 **Objective:** Users can verify what the model predicts and whether it is actually accurate.