docs: use English docs for some external links in README

currently we have no polished English version of some docs (quickstart, use case, standalone vs cluster), so the links in README all point to Chinese docs. We need to replace them with English versions.

The README file needs to be located in the repository root. Find the links to the Chinese documentation for quickstart, use case, and standalone vs cluster. Replace these links with the corresponding English documentation URLs if they exist. Verify the changes by checking the README rendering.

索引モデルが issue の本文から書いたものです。