housekeeping.yml (daily sweep, #83) and its test in ci.yml

The sweep itself landed in #115; the workflow is the owner's merge. Dry-run unless TIME_MODE=live (which the repo sets).

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017K4vyY3yUD3GsvoZaAtKkD

.github/workflows/ci.yml

@@ -19,3 +19,4 @@ jobs:
           node-version: 22
       - run: python3 .github/time/test_time.py
       - run: python3 .github/time/test_seed.py
+      - run: python3 .github/time/test_housekeeping.py