Defines two backward-compatible mechanisms for accurate route state tracking: heartbeat extension (routeStates map in heartbeat body) and ROUTE_STATE_CHANGED events for real-time updates. Covers agent-side detection via Camel EventNotifier, server-side handling, multi-agent conflict resolution, and migration path. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>