# Log
- 2026-10-30 P0: read TASK.md, wrote contract.
- 2026-10-30 P1: audit found 0 post_cut=1 rows (sample ends 2019-12-31). Decision: premise_invalid, no proxies.
- 2026-10-30 P2: baseline mean one-day change over whole file = -0.042851 bp.
- 2026-10-30 P3: analysis.py written (Welch path implemented but not reachable with this data); outputs written.
- 2026-10-30 P4: clean re-run identical; checks recorded.
- 2026-10-30 P5: report and claims written; all phases passed (task outcome: infeasible by design of data).