Feature: tinyTikTok 数据库表设计

**Is your feature request related to a problem? Please describe.**
- 目前没有看到数据的底层存储方案

**Describe the solution you'd like**
API接口说明：https://www.apifox.cn/apidoc/shared-09d88f32-0b6c-4157-9d07-a36d32d7a75c/api-50707525
设计对应的数据存储方案，给出表设计和sql文件

tinyTikTok 基础接口
#7
#9
- [x] 用户表
- [x] 视频表

tinyTikTok 互动接口（待定）
- [x] 点赞表
- [x] 评论表

tinyTikTok 社交接口（待定）
- [ ] 关注表
- [ ] 粉丝表
- [ ] 聊天记录

**Describe alternatives you've considered**
None.

**Additional context**
None.

Start with the linked API documentation and related issues #7 and #9, noting the existing user, video, like, and comment tables. Design storage for the remaining social interfaces—following, followers, and chat records—and provide the corresponding table definitions and SQL file; done means the requested schema and SQL are documented for these interfaces.

Written by the indexing model from the issue text.