fix: remove trailing comma in hotspot POST — was returning (Response, None) tuple

app.py

@@ -180,7 +180,7 @@ def hotspot_config_update():
             )
         return jsonify(message=f"Hotspot SSID updated to '{ssid}'."
                                + (" Password saved." if password else "")
-                               + " Restart hotspot or device to apply."),
+                               + " Restart hotspot or device to apply.")
     except subprocess.CalledProcessError as e:
         return jsonify(error=f"Could not update hotspot: {e.stderr.strip() or 'nmcli failed'}"), 500