fix(prod-readiness r2): signer-ARN normalization (P0) + metric fixes [qa twin of #315]
- fix(prod-readiness r2): signer-ARN normalization, store-avg status gate, canonical category means, CI lock-tests
- Merge pull request #316 from tpromni/release/prod-readiness-2026-07-r2
Source: tpromni/coach-pulse-consumer-ui → qa