feat: wire BLE scan broadcasts to dashboard WebSocket

Connect bleRegistry to the dashboard hub so ble_scan messages are
broadcast every 5s to all connected dashboard clients. Add rssi,
last_seen, and blob_id fields to GetCurrentDevices output to match
the frontend's expected message format.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

mothership/cmd/mothership/main.go

@@ -652,6 +652,11 @@ func main() {
 
     dashboardHub.SetIngestionState(ingestSrv)
 
+    // Wire BLE state to dashboard for ble_scan broadcasts (5s interval)
+    if bleRegistry != nil {
+        dashboardHub.SetBLEState(bleRegistry)
+    }
+
     // Wire zone state to dashboard for occupancy snapshots
     if zonesMgr != nil {
         dashboardHub.SetZoneState(&zoneStateAdapter{mgr: zonesMgr})
@@ -674,9 +679,10 @@ func main() {
         }()
     }
 
-    // Wire ingestion → dashboard for CSI and motion broadcasts
+    // Wire ingestion → dashboard for CSI, motion, and event broadcasts
     ingestSrv.SetDashboardBroadcaster(dashboardHub)
     ingestSrv.SetMotionBroadcaster(dashboardHub)
+    ingestSrv.SetEventBroadcaster(dashboardHub)
 
     // Phase 6: Wire BLE messages to registry and identity matcher
     ingestSrv.SetBLEHandler(func(nodeMAC string, devices []ingestion.BLEDevice) {

mothership/internal/ble/registry.go

@@ -1373,10 +1373,13 @@ func (r *Registry) GetCurrentDevices() []map[string]interface{} {
 	result := make([]map[string]interface{}, len(devices))
 	for i, d := range devices {
 		result[i] = map[string]interface{}{
-			"mac":           d.Addr,
-			"name":          d.Name,
-			"label":         d.Label,
-			"manufacturer":  d.Manufacturer,
+			"mac":            d.Addr,
+			"name":           d.Name,
+			"label":          d.Label,
+			"rssi":           d.RSSIAvg,
+			"last_seen":      d.LastSeenAt.UnixMilli(),
+			"blob_id":        nil,
+			"manufacturer":   d.Manufacturer,
 			"device_type":   d.DeviceType,
 			"device_name":   d.DeviceName,
 			"mfr_id":        d.MfrID,