Workflows batch: heartbeat knobs, housekeeping.yml, its test in CI (#127)

Workflows batch: heartbeat knobs, housekeeping.yml, its test in CI (#127)

heartbeat.yml passes TIME_CAP_SLACK, TIME_ANTHROPIC_API (the caching kill switch), TIME_REVIEW_TIEBREAK and TIME_REVIEW_QUORUM; housekeeping.yml runs the daily sweep at 13:17 UTC; ci.yml runs test_housekeeping.py. Owner-approved merge.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017K4vyY3yUD3GsvoZaAtKkD

.github/workflows/housekeeping.yml

@@ -0,0 +1,26 @@
+name: housekeeping
+# The daily sweep (#83, .github/time/housekeeping.py): prunes merged branches, closes spent signal issues and empty
+# milestones, lists the stale on the Astra log. Deterministic, no model calls; dry-run unless TIME_MODE=live.
+# SOP: .agents/skills/housekeeping/SKILL.md
+on:
+  schedule:
+    - cron: "17 13 * * *"   # a few minutes after the Astra tick (13:13)
+  workflow_dispatch:
+concurrency:
+  group: housekeeping
+  cancel-in-progress: false
+jobs:
+  sweep:
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+    steps:
+      - uses: actions/checkout@v5
+        with:
+          sparse-checkout: .github/time
+          persist-credentials: false
+      - run: python3 .github/time/housekeeping.py
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          TIME_TOKEN: ${{ secrets.TIME_TOKEN }}   # branch and issue writes go out as the `time` user
+          TIME_MODE: ${{ vars.TIME_MODE }}
+          TIME_VENTURE_MEASURE_DAYS: ${{ vars.TIME_VENTURE_MEASURE_DAYS }}