fix: retry UDP discovery once if first attempt finds no devices

internal/api/handlers.go

@@ -132,6 +132,9 @@ func (h *Handler) ensureDevicesLoaded() {
 		return
 	}
 	_, _ = h.discovery.SearchDefault()
+	if len(h.registry.GetDevices()) == 0 {
+		_, _ = h.discovery.SearchDefault()
+	}
 }
 
 func (h *Handler) ProxyAgent(w http.ResponseWriter, r *http.Request) {

internal/web/ui.go

@@ -704,6 +704,10 @@ func (u *UI) ensureDevicesLoaded() {
 		return
 	}
 	_, _ = u.discovery.SearchDefault()
+	// Retry once if discovery returned nothing (UDP broadcast can be lossy on some networks)
+	if len(u.registry.GetDevices()) == 0 {
+		_, _ = u.discovery.SearchDefault()
+	}
 }
 
 func (u *UI) pageDashboard(w http.ResponseWriter, r *http.Request) {