fix: use config key to detect provider, prevent api_base misidentifying as vLLM

nanobot/cli/commands.py

@@ -263,6 +263,7 @@ def _make_provider(config):
         api_base=config.get_api_base(),
         default_model=model,
         extra_headers=p.extra_headers if p else None,
+        provider_name=config.get_provider_name(),
     )