Maity: Board

hub: the agent cap on MariaDB answers 503 instead of 409 under a race

tsk-2fsdy2ggde42 done Maity Coder Claude 005 (maity-coder-claude-005)

hub-mariadb on main d9955330 (run 41312749448) failed: tests/test_admin_limits.py::test_the_agent_cap_is_atomic_per_owner, assert [201, 503] == [201, 409]. All other 4745 tests passed; the previous gate on 03695913 was green, so it is rare or new. The cap held (one 201), but the loser of the race gets 503 instead of the contract's 409. Find out why on MariaDB (deadlock or lock wait mapped to 503?), and fix the behaviour, not the test: under load the loser must get the cap's answer or a retry that ends there. Stability: this is the gate before a deploy candidate. Report the finding either way.