---

This section details on the original issue you should resolve

<issue_title>为什么要给state绑一个max255的限制&强制校验code_challenge_method</issue_title>
<issue_description>Describe the bug
在进行 OAuth2/OIDC 授权请求时，GrantService 接口返回参数校验失败错误。具体表现为 state 字段长度超出限制，且 code_challenge_method 字段与预设的 S256 约束不匹配。

To Reproduce
http://localhost/session/authorize?client_id=c2929a-929a-4d3b-929a-bdcfb266c7e9&redirect_uri=https://oauth.localhost.cn/callback&scope=openid%20profile%20email&response_type=code&state=P2NsaWVudF9pZD05NTA1Yjc3N2ZmNmY2NDdmODIxMyZjb2RlX2NoYWxsZW5nZT1SUGhOb0pqdGpOc015N3h5MmVrVjdTbHFLTVNabTE2bVlUTElsX29tVGhjJmNvZGVfY2hhbGxlbmdlX21ldGhvZD1TMjU2JnJlZGlyZWN0X3VyaT1odHRwJTNBJTJGJTJGbG9jYWxob3N0JTNBMzAwMCUyRmF1dGglMkZjYWxsYmFjayZyZXNwb25zZV90eXBlPWNvZGUmc2NvcGU9b3BlbmlkK3Byb2ZpbGUrZW1haWwmc3RhdGU9SnBkdUVNQ0wyOWJ3VklOWnNEOUdleHBKTVZvdHh2R1omYXBwbGljYXRpb249THVtaW5ldC1BdXRoJnByb3ZpZGVyPWx1bWluZXRfcGFuJm1ldGhvZD1zaWdudXA=
POST /api/v4/session/oauth/consent
{"client_id":"c2929a-929a-4d3b-929a-bdcfb266c7e9","response_type":"code","redirect_uri":"https://oauth.localhost.cn/callback","state":"P2NsaWVudF9pZD05NTA1Yjc3N2ZmNmY2NDdmODIxMyZjb2RlX2NoYWxsZW5nZT1SUGhOb0pqdGpOc015N3h5MmVrVjdTbHFLTVNabTE2bVlUTElsX29tVGhjJmNvZGVfY2hhbGxlbmdlX21ldGhvZD1TMjU2JnJlZGlyZWN0X3VyaT1odHRwJTNBJTJGJTJGbG9jYWxob3N0JTNBMzAwMCUyRmF1dGglMkZjYWxsYmFjayZyZXNwb25zZV90eXBlPWNvZGUmc2NvcGU9b3BlbmlkK3Byb2ZpbGUrZW1haWwmc3RhdGU9SnBkdUVNQ0wyOWJ3VklOWnNEOUdleHBKTVZvdHh2R1omYXBwbGljYXRpb249THVtaW5ldC1BdXRoJnByb3ZpZGVyPWx1bWluZXRfcGFuJm1ldGhvZD1zaWdudXA=","scope":"openid profile email"}
在Debug模式下返回{
"code": 40001,
"msg": "State too long",
"error": "Key: 'GrantService.State' Error:Field validation for 'State' failed on the 'max' tag\nKey: 'GrantService.CodeChallengeMethod' Error:Field validation for 'CodeChallengeMethod' failed on the 'eq' tag"
}
Expected behavior
不应该限制state的大小&为什么强制要求code_challenge_method参数
Screenshots
If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: macOS 14
• Browser chrome
• Version pro 4.12.4 #fa35b18

Additional context
Add any other context about the problem here.
</issue_description>

<agent_instructions>Fix it and limit state to 4KB</agent_instructions>

Comments on the Issue (you are @copilot in this section)