fix: source_events_per_minute=0 must block all events, not disable th…

[manishmcsa01-cmd]

…e limit

Bug: In AutonomyGovernor.admit_event(), the guard:
if self.source_events_per_minute > 0:
skips the rate limit entirely when the value is 0. An operator setting source_events_per_minute=0 intends 'block all events from any source', but actually gets 'allow unlimited events' -- the control does not hold.

This is exactly the kind of bug the session warns about: a ceiling that resets to infinity at the boundary value.

Fix: Change the guard to >= 0 and handle the zero case explicitly by refusing immediately with a clear reason.

Test: test_zero_source_rate_limit_blocks_all_events fails before this change (verdict.admitted is True) and passes after (admitted is False).

[theschoolofai]

Session 16 — graded ✅

Score: +100.

source_events_per_minute=0 disabled the limiter instead of blocking every event, so the strictest setting was the most permissive. A falsy-zero defect on a security control.