feat: implement chatbot engine for project idea and feature generation

src/recommendation_engine/chatbot_engine.py

@@ -1231,6 +1231,10 @@ Choose what you want:
         
         if is_question and "other" not in text_lower:
             # Answer conversational question directly via LLM
+            history_text = "\n".join(
+                f"User: {h.get('user', '')}\nBot: {h.get('bot', '')}"
+                for h in history[-3:]
+            )
             prompt = build_chat_prompt(state)
             full_prompt = (
                 f"{prompt}\n\n"