Skip node DB fetch during --ota-update / --reboot-ota

OTA only needs the local node to send the startOTA admin request and then
streams firmware directly to the loader over WiFi; it never reads the node DB.
On a device with a large node DB the initial dump can stall and the firmware
closes the API connection before it processes the OTA request, so OTA silently
fails. Imply --no-nodes for --ota-update / --reboot-ota.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

meshtastic/__main__.py

@@ -1590,6 +1590,12 @@ def common():
             if not os.path.isfile(args.ota_update):
                 meshtastic.util.our_exit(f"Error: OTA firmware file not found: {args.ota_update}", 1)
 
+        # OTA (WiFi/BLE) only needs the local node to send the admin request and then
+        # streams the firmware directly; it never reads the node DB. Skip fetching it so a
+        # large node DB dump can't stall/close the connection before the OTA request lands.
+        if getattr(args, "ota_update", None) or getattr(args, "reboot_ota", False):
+            args.no_nodes = True
+
         if have_powermon:
             create_power_meter()