The contributor's 15-test module pinned encoding details (frozen-arg shapes,
postponed-annotation resolution, monkeypatch seams). The two behaviour
contracts that matter survive: a 12-request /api/profiles burst admits ONE
worker and leaves /api/status responsive on a 2-token pool (this file), and
the kanban board read shares one worker per key (test_kanban_read_admission).
Both go red when the coalescing wrapper is removed from the route.