Add HF token fallback in agent.py

src/agent.py

@@ -28,11 +28,13 @@ class ProjectAgent:
         """Initialize the agent."""
         self.rag = rag
         # Use HF Inference API (free tier)
+        # HF Spaces provides token as HF_TOKEN or HUGGING_FACE_HUB_TOKEN
+        hf_token = os.getenv("HF_TOKEN") or os.getenv("HUGGING_FACE_HUB_TOKEN")
         llm = HuggingFaceEndpoint(
             repo_id=model_name,
             temperature=0.1,
             max_new_tokens=512,
-            huggingfacehub_api_token=os.getenv("HF_TOKEN")
+            huggingfacehub_api_token=hf_token
         )
         self.llm = ChatHuggingFace(llm=llm)
         self.graph = self._build_graph()