[Feature]: OAuth 登录要能够支持通过邮件关联已有账户

[Noxiven]

Affected area

Authentication / authorization

Problem or use case

OAuth 登录要能够支持通过邮件关联已有账户

Proposed behavior

OAuth 登录要能够支持通过邮件关联已有账户

Alternatives considered

No response

Compatibility, deployment, or migration impact

No response

Documentation or API contract impact

No response

Pre-submit checklist

• I searched existing issues and pull requests.
• This request is focused on one feature or improvement.
• I described user-facing, API, configuration, or deployment impact where relevant.