fix: rename query param device->device_id in telemetry API (v0.2.6)

- GET /telemetry?device_id= now consistently uses device_id
- was: ?device= (inconsistent with response field name)
- found during extended test suite

internal/api/handler/iot_telemetry_handler.go

@@ -28,7 +28,7 @@ func (h *Handler) ListIoTTelemetry(w http.ResponseWriter, r *http.Request) {
 	}
 
 	ns := mux.Vars(r)["namespace"]
-	deviceID := r.URL.Query().Get("device")
+	deviceID := r.URL.Query().Get("device_id")
 	limit := 50
 	if ls := r.URL.Query().Get("limit"); ls != "" {
 		if n, err := strconv.Atoi(ls); err == nil && n > 0 {