- Emulator: add sip_gateway field to all scenarios (auto-trunk creation)
- Makefile: build-agent, build-siptest, emulate-*, siptest-* targets
- README: full documentation with agent section, production deployment
- Project structure update with all components
- SIPGateway field in NodeMetric model
- HasNode() engine method
- OnNewNode callback in NATS subscriber
- Auto-create balance trunk from new node metric
- BroadcastGatewayEvent on WS hub
- Gateway status indicators in trunks UI (green/red/gray)
- SPA fallback for frontend routing