The chained-fused-dispatch spelling fix (0dc2fe90) was whack-a-mole: each
unrecognized dispatch spelling silently drops a producer edge from the
generated matrix, and only a human reading the table catches it. Convert the
class to a build failure: the generator now hard-errors when any DECLARED
event ends with zero dispatchers — dead vocabulary or a missed spelling,
both actionable ('teach the scan or add a DYNAMIC_EVENT_DISPATCHERS
override'). Zero LISTENERS stays legal: seven current rows (agent/request,
system-prompt/assemble, tools/change, ...) are ordinary extension points
dispatched for out-of-repo plugins.
The guard caught a real one on its first run: subagent/provider-removed
routes through the same contained events.dispatch as subagent/start|end
(it fires inside the provider registration's disposer), but the
DYNAMIC_EVENT_DISPATCHERS override list never got an entry when that
containment routing was introduced — the committed matrix (on master too)
claimed the event has NO dispatcher while tool-subagent listens for it.
Override added; matrix regenerated with the producer edge restored.