fix: Fix authentication issue in Nexus Gateway client (#690)

Co-authored-by: Maryam Khidir <[email protected]>

Author: maryamkhidir

lib/shared/layers/python-sdk/python/genai_core/model_providers/nexus/nexus.py

@@ -7,7 +7,7 @@
 from functools import lru_cache
 from typing import Any, Optional, Union
 
-from genai_core.types import EmbeddingsModel, Provider
+from genai_core.types import EmbeddingsModel, Provider, ModelInterface
 
 from ... import parameters
 from .. import ModelProvider
@@ -156,4 +156,5 @@ def _transform_nexus_model(
         "streaming": streaming,
         "inputModalities": input_modalities,
         "outputModalities": output_modalities,
+        "interface": ModelInterface.LANGCHAIN.value,
     }

lib/shared/layers/python-sdk/python/genai_core/model_providers/nexus/nexus_client.py

@@ -114,7 +114,7 @@ def _make_request(
         # Use client credentials
         token = self._ensure_valid_token()
         if token:
-            request_headers["Authorization"] = f"Bearer {token}"
+            request_headers["authorization-token"] = f"Bearer {token}"
         else:
             logger.error("Failed to get access token for Nexus Gateway")
             return ApiError(