feat(logging): log user questions and AI responses

logs.py

@@ -0,0 +1,13 @@
+from datetime import datetime
+
+
+def save_log(user_id: int, history: dict, response: str):
+    log_entry = (
+        f"[{datetime.now().isoformat(sep=' ', timespec='seconds')}]\n"
+        f"Usuário: {user_id}\n"
+        f"Histórico: {history}\n"
+        f"Recomendação: {response.strip()}\n"
+        f"{'-'*40}\n"
+    )
+    with open("recommender.log", "a", encoding="utf-8") as f:
+        f.write(log_entry)