Include reporter in endpoint health report

agents/rap-node-agent/cmd/rap-node-agent/main.go

@@ -500,6 +500,7 @@ func (s *vpnFabricEndpointObservationStore) Report(observedAt time.Time, maxEntr
 	if len(snapshot) == 0 {
 		return map[string]any{
 			"schema_version":   "rap.vpn_fabric_endpoint_health_report.v1",
+			"reporter_node_id": s.reporterNodeID,
 			"observed_at":      observedAt.UTC().Format(time.RFC3339Nano),
 			"total":            0,
 			"reported":         0,
@@ -523,6 +524,7 @@ func (s *vpnFabricEndpointObservationStore) Report(observedAt time.Time, maxEntr
 	reported := values[:maxEntries]
 	return map[string]any{
 		"schema_version":   "rap.vpn_fabric_endpoint_health_report.v1",
+		"reporter_node_id": s.reporterNodeID,
 		"observed_at":      observedAt.UTC().Format(time.RFC3339Nano),
 		"total":            len(values),
 		"reported":         len(reported),

agents/rap-node-agent/cmd/rap-node-agent/main_test.go

@@ -804,6 +804,7 @@ func TestVPNFabricEndpointObservationReportIsBoundedAndNewestFirst(t *testing.T)
 	}
 	report := store.Report(base, 1)
 	if report["schema_version"] != "rap.vpn_fabric_endpoint_health_report.v1" ||
+		report["reporter_node_id"] != "node-a" ||
 		report["total"] != 2 ||
 		report["reported"] != 1 ||
 		report["dropped"] != 1 {

docs/architecture/DISTRIBUTED_FABRIC_NODE_PROTOCOL_PLAN.md

@@ -345,6 +345,8 @@ those remote health hints with local observations using the newest signal.
 Endpoint health observations include source and reporter node fields so control
 plane can distinguish local dial feedback from aggregated or policy-generated
 health hints.
+The endpoint health heartbeat report also includes the reporter node id at the
+report level for simpler multi-node ingestion and diagnostics.
 
 Deliverables: