Implements Phase 4 of the go-p2p task queue. The Dispatcher routes
HMAC-verified UEPS packets to registered IntentHandlers by IntentID,
enforcing a threat circuit breaker that drops packets with ThreatScore
exceeding 50,000 (logged as threat events at WARN level).
Design choices:
- IntentHandler is a func type (not interface) for lightweight registration
- 1:1 mapping of IntentID to handler, replacement on re-register
- Threat check fires before intent routing (hostile packets never reach handlers)
- Sentinel errors (ErrThreatScoreExceeded, ErrUnknownIntent, ErrNilPacket)
- RWMutex protects handler map for concurrent safety
Tests: 10 test functions, 17 subtests — 100% dispatcher coverage.
Race detector clean. All 102 existing tests continue to pass.
Co-Authored-By: Charon <developers@lethean.io>