Stub and LLM paths both read loop.DownServices, so the message can never name
a service the predicate did not fire on. Two down at once are both named — he
needs the blast radius.
ExplainTick and ExplainGate produce a full TickTrace for every tick,
recording per-rule: predicate result, gate result, first gate blocker,
gate detail (snooze/cooldown/presence etc.), and win/loss info.
IPC layer: new MethodTickTrace, DTOs (TickTrace, RuleTrace, GateDetail),
dispatch, client proxy, and CoreAPI interface method.
Daemon: tickLoop caches the latest trace; daemonAPI wraps storeAPI
with a TickTrace override that returns the cached trace.
Tests: 15 new tests for ExplainGate (all blockers, bypass conditions,
ordering) and ExplainTick (nothing fires, one fires, tiebreak,
winner/lost_to recording, gate-blocked recording).