搜索排名

可以考虑加个搜索功能，输入 GitHub ID 看排名，比如输入 `jaywcjlove` 看看自己的排名，输入仓库名称看 star 排名。需要看下是否有 API 支持，纯属好奇😀

Start by checking the repository's existing GitHub API integration and whether the API supports searching users by GitHub ID and repositories by name. Trace how rankings are currently generated, then define the search entry point and verify that both user rankings and repository star rankings can be returned. Done means both search cases work with clear results.

Written by the indexing model from the issue text.