Reserve daily run slots atomically under concurrent events

[Prerit-112]

Summary

• admit_run() checked max_runs_per_day / daily_budget against the window ledger, but the run was only recorded after runtime.run() finished.
• Concurrent process() calls could all observe count/spend = 0 and all start runs, so the daily ceilings did not hold under overlap — a control that looks correct sequentially but fails when events arrive together.
• Fix: atomically reserve a run slot (and daily-budget remainder when set) under the event-store lock at admit time; settle actual spend after the run without double-counting.

What breaks (before)

1. Subscription with max_runs_per_day=1.
2. Fire several overlapping relevant events (asyncio.gather on engine.process).
3. Observe multiple runs and zero (or too few) max_runs_per_day refusals — the ceiling is bypassed.

Fix

• EventStore.window_try_admit_run — check ceilings and reserve count / reserved USD in one locked section.
• EventStore.window_settle_run — replace reserved budget with metered spend (count already reserved).
• AutonomyGovernor.admit_run / settle_run + engine path updated accordingly; failed runs refund reserved budget but keep the consumed slot.

Test plan

• pytest tests/test_autonomy_governor.py — includes new concurrent ceiling test; red before fix on that case, green after
• Sequential max_runs_per_day still bounds runs and records refusals
• Sequential daily_budget still caps the window and shrinks effective per-run budget
• Concurrent events with max_runs_per_day=1 → exactly one run and three max_runs_per_day refusals
• Self-trigger, source rate limit, triage ceiling, liveness, and morning-report tests still pass
• Reviewer: confirm diff has no .env, tokens, credentials, or local EA wiring
• Reviewer: optional — concurrent daily_budget stress (same pattern as max_runs) if desired beyond the unit test

No secrets, real messages, or API keys in this diff.

[theschoolofai]

Session 16 — graded

Score: 0.

Duplicate of #3, filed 2026-08-09 against this one's 08-12. Same daily-ceiling race, same files, same atomic-reservation fix.

[theschoolofai]

Session 16 — regraded ✅

Score: +100. The verdict below stands: this is a duplicate of an earlier filing (or, for glc_v5 #23, an enhancement rather than a defect), and it is recorded as such.

What has changed is the credit. On review, the work here was genuinely done: the bug was found independently, the reproduction is real and the fix is sound. Losing a race you had no way of seeing is not a reason to earn nothing, so this is credited at the full 100 even though it does not carry the first-to-file claim.

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Original assessment, unchanged:

Duplicate of #3, filed 2026-08-09 against this one's 08-12. Same daily-ceiling race, same files, same atomic-reservation fix.