feat(git): add SSH keychain configuration guide

- Add comprehensive SSH key management with macOS Keychain

- Include troubleshooting for password prompt issues

- Document 1Password agent conflicts and solutions

skill/git/SKILL.md

@@ -13,6 +13,7 @@ You are an expert in Git version control and repository management.
 |------|------|
 | [Commit Workflow](./commit-workflow.md) | 提交暂存文件，自动生成提交信息并创建版本标签 |
 | [Push Workflow](./push-workflow.md) | 提交并推送到远程仓库的完整工作流 |
+| [SSH Keychain](./ssh-keychain.md) | SSH 密钥管理与 macOS Keychain 自动解锁配置 |
 
 ## Core Principles