Add Git remote repository documentation

[Copilot]

Addresses user question: "怎么关联远程仓库" (How to associate a remote repository)

Added bilingual (Chinese/English) documentation covering Git remote operations:

• Add remote: git remote add origin <url>
• View remotes: git remote -v
• Update URL: git remote set-url origin <url>
• Remove remote: git remote remove origin
• Push/pull: git push -u origin main / git pull origin main

Each operation includes practical examples with placeholder values.

Original prompt

怎么关联远程仓库

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✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.