migrate 392 questions to pattern format

backend/data/questions/design-twitter.yaml

@@ -7,7 +7,8 @@ categories:
   - hash-tables
   - heap
 patterns:
-  - heap
+  - slug: heap
+    is_optimal: true
 
 function_signature: "class Twitter:\n    def __init__(self): ...\n    def post_tweet(self, user_id: int, tweet_id: int) -> None: ...\n    def get_news_feed(self, user_id: int) -> list[int]: ...\n    def follow(self, follower_id: int, followee_id: int) -> None: ...\n    def unfollow(self, follower_id: int, followee_id: int) -> None: ..."