Log
- 2026-10-30 P0: read TASK.md, wrote contract.
- 2026-10-30 P1: audited data; README discrepancy on 1992-01 empties noted; no exclusions beyond spec window.
- 2026-10-30 P2: baselines naive/mean computed in analysis.py (same rolling evaluation).
- 2026-10-30 P3: ridge implemented exactly per spec; added DM (HLN) tests as extra uncertainty keys. Decision: no random seed needed (null).
- 2026-10-30 P4: verification checks all pass (see checks.md); gate run.
- 2026-10-30 P5: report + claims written; gate PASSED (receipt 20261030T041020.597944Z). All phases passed.