Fix st.chat_input outside columns

streamlit_app/app.py

@@ -259,6 +259,9 @@ if not st.session_state.pipeline:
         st.markdown(f"- {query}")
 
 else:
+    # Chat input MUST be outside columns/containers
+    user_input = st.chat_input("Ask a question about the Agentic AI eBook...")
+    
     # Chat interface
     col1, col2 = st.columns([2, 1])
     
@@ -273,9 +276,6 @@ else:
                 with st.chat_message(message["role"]):
                     st.write(message["content"])
         
-        # Chat input
-        user_input = st.chat_input("Ask a question about the Agentic AI eBook...")
-        
         if user_input:
             # Add user message to chat
             st.session_state.messages.append({"role": "user", "content": user_input})