refactor: 教学版移除全平台用户个人信息采集与持久化

- 用户 ID 转为匿名 creator_hash，昵称中间脱敏，IP/头像/主页/签名/性别不再采集
- 覆盖 xhs/weibo/bilibili/douyin/kuaishou/tieba/zhihu 7 个平台
- 删除 7 张 creator 档案 ORM 表，15 张内容/评论表新增 creator_hash 列
- B 站禁用粉丝/关注/联系人列表抓取
- 新增 tools/user_hash.py 与 4 个平台的 mock+SQLite 端到端测试

测试: pytest tests/test_no_user_info.py tests/test_weibo_no_user_info.py tests/test_douyin_no_user_info.py tests/test_kuaishou_no_user_info.py (21 passed)

store/kuaishou/_store_impl.py

@@ -228,21 +228,8 @@ class KuaishouMongoStoreImplement(AbstractStore):
         utils.logger.info(f"[KuaishouMongoStoreImplement.store_comment] Saved comment {comment_id} to MongoDB")
 
     async def store_creator(self, creator_item: Dict):
-        """
-        Store creator information to MongoDB
-        Args:
-            creator_item: Creator data
-        """
-        user_id = creator_item.get("user_id")
-        if not user_id:
-            return
-
-        await self.mongo_store.save_or_update(
-            collection_suffix="creators",
-            query={"user_id": user_id},
-            data=creator_item
-        )
-        utils.logger.info(f"[KuaishouMongoStoreImplement.store_creator] Saved creator {user_id} to MongoDB")
+        # 教学版：创作者个人资料不再落库
+        pass
 
 
 class KuaishouExcelStoreImplement: