fix(config_flow): no_state_source fires only when none of the three sources is present — ADB-only standalone is valid; strings/docs name all three (F2)

custom_components/nvidia_shield/strings.json

@@ -54,7 +54,7 @@
       "protocol_no_host": "Could not determine the Shield's IP address. Set the Protocol Host or ADB Host field.",
       "protocol_invalid_code": "Pairing has not started or the code is empty. Click Submit to retry.",
       "protocol_pair_failed": "The Shield rejected that pairing code. Click Submit to try again.",
-      "no_state_source": "No state source selected. Link the Android TV Remote entity or enable the Nvidia Remote Protocol pairing \u2014 the integration needs at least one source of power/app state."
+      "no_state_source": "No state source selected. Provide at least one of: the Android TV Remote entity, the Nvidia Remote Protocol pairing, or ADB media-session mode (enable ADB and set the ADB Host)."
     },
     "abort": {
       "already_configured": "This Shield entity is already configured.",