Improve API key handling to support both environment variables and Streamlit secrets

src/streamlit_app.py

@@ -39,10 +39,25 @@ AGE_CONTEXT = {
 
 # Handle API key setup
 try:
+    # Try multiple ways to get the API key
+    api_key = None
+    
+    # Try environment variable
     api_key = os.getenv("ANTHROPIC_KEY")
+    
+    # Try Streamlit secrets if env var not found
+    if not api_key and hasattr(st, 'secrets'):
+        api_key = st.secrets.get("ANTHROPIC_KEY")
+    
     if not api_key:
-        st.error("Anthropic API key not found. Please set the ANTHROPIC_KEY environment variable.")
+        st.error("""
+        ⚠️ Anthropic API key not found. Please make sure:
+        1. You've added the secret in Hugging Face Space settings
+        2. The secret is named exactly 'ANTHROPIC_KEY'
+        3. The Space has been rebuilt after adding the secret
+        """)
         st.stop()
+        
     c = Anthropic(api_key=api_key)
 except Exception as e:
     st.error(f"Error initializing Anthropic client: {str(e)}")