Add LED ring control per client and broadcast over REST and WebSocket.

Solid color mode fills all ring LEDs; master routes UART commands to slaves
via ESPNOW_LED_RING. goTool exposes POST /api/led-ring, WebSocket set_led_ring,
and a dashboard LED panel with master/slave/all targets.

Co-authored-by: Cursor <cursoragent@cursor.com>

goTool/api_stream.go

@@ -132,7 +132,9 @@ func (h *accelStreamHub) register(conn *websocket.Conn, portName string) *wsSubs
 		Type:       "hello",
 		Serial:     portName,
 		IntervalMs: int(h.defaultInterval / time.Millisecond),
-		Commands:   []string{"set_stream", "get_stream", "set_accel_stream", "get_accel_stream"},
+		Commands: []string{
+			"set_stream", "get_stream", "set_accel_stream", "get_accel_stream", "set_led_ring",
+		},
 	}
 	if data, err := json.Marshal(hello); err == nil {
 		_ = conn.WriteMessage(websocket.TextMessage, data)
@@ -317,6 +319,15 @@ func writeStreamStatus(conn *websocket.Conn, msg StreamStatusMessage) {
 	_ = conn.WriteMessage(websocket.TextMessage, data)
 }
 
+func writeLedRingStatus(conn *websocket.Conn, out ledRingAPIResponse) {
+	out.Type = "led_ring_status"
+	data, err := json.Marshal(out)
+	if err != nil {
+		return
+	}
+	_ = conn.WriteMessage(websocket.TextMessage, data)
+}
+
 func writeAccelStreamStatus(conn *websocket.Conn, out accelStreamAPIResponse) {
 	msg := AccelStreamStatusMessage{
 		Type:          "accel_stream_status",
@@ -393,10 +404,22 @@ func handleAccelWSCommand(conn *websocket.Conn, sub *wsSubscriber, data []byte,
 			Success:  resp.GetSuccess(),
 		})
 
+	case "set_led_ring":
+		var body ledRingAPIRequest
+		if err := json.Unmarshal(data, &body); err != nil {
+			writeLedRingStatus(conn, ledRingAPIResponse{Error: "invalid JSON"})
+			return
+		}
+		if body.Mode == "" {
+			writeLedRingStatus(conn, ledRingAPIResponse{Error: "mode required"})
+			return
+		}
+		writeLedRingStatus(conn, applyLedRing(link, body))
+
 	default:
 		writeStreamStatus(conn, StreamStatusMessage{
-			Type:  "stream_status",
-			Error: "unknown type (set_stream, get_stream, set_accel_stream, get_accel_stream)",
+			Type: "stream_status",
+			Error: "unknown type (set_stream, get_stream, set_accel_stream, get_accel_stream, set_led_ring)",
 		})
 	}
 }
@@ -434,7 +457,7 @@ func mountExternalAPI(mux *http.ServeMux, portName string, defaultInterval time.
 			DefaultIntervalMs: defMs,
 			MinIntervalMs:     int(minAPIStreamInterval / time.Millisecond),
 			MaxIntervalMs:     int(maxAPIStreamInterval / time.Millisecond),
-			Description:       "WebSocket: per-connection accel receive + interval; slave stream via set_accel_stream",
+			Description:       "WebSocket: accel stream + set_led_ring (modes: clear, color, progress, digit, blink, find-me)",
 		})
 	})
 
@@ -454,6 +477,7 @@ func runAPIServer(portName string, link *managedSerial, addr string, defaultInte
 
 	mux := http.NewServeMux()
 	mountExternalAPI(mux, portName, defaultInterval, hub, link, dash, ctl)
+	mountLedRingAPI(mux, link)
 
 	srv := &http.Server{Addr: addr, Handler: mux}
 	go func() {