feat: migrate Gemini 3 Pro High/Low to Gemini 3.1 Pro High/Low

[omergulen]

Summary

This PR migrates Gemini Pro High/Low model IDs from Gemini 3 to Gemini 3.1:

• gemini-3-pro-high -> gemini-3.1-pro-high
• gemini-3-pro-low -> gemini-3.1-pro-low

Scope

• Migrated only Pro High/Low paths and related routing/config/sync/UI references.
• Added compatibility mapping so legacy gemini-3-pro-* IDs still resolve correctly.
• Did not migrate Flash models.
• Did not migrate image models.

Validation

• Passed targeted migration tests:
  • proxy::common::model_mapping::tests::*
  • proxy::opencode_sync::tests::*
  • proxy::tests::quota_protection::tests::test_monitored_models_normalization_consistency
• Frontend build passes (npm run build).
• Full Rust suite still has pre-existing baseline failures that also reproduce on origin/main.

Resolves

• Error when use model Gemini 3.1 Pro #2041
• 提示我需要使用gemini 3.1 pro #2051
• 关于如何不更新版本使用gemini 3.1 pro #2052
• Can you add Gemini 3.1 pro for new version ? #2054
• 什么时候增加一下反代的 3.1 系列模型 #2061

[hikenshi]

Can you add sonnet-4-6 too?

[omergulen]

Can you add sonnet-4-6 too?

Isn't this PR for that? #2014

[hikenshi]

Can you add sonnet-4-6 too?

Isn't this PR for that? #2014

Thank you

[1sjan]

Hello, I am encountering the following error:

All accounts exhausted. Last error: HTTP 403: { "error": { "code": 403, "message": "Verify your account to continue.", "status": "PERMISSION_DENIED" }

Currently, I can use any Gemini 2-series models, but I am unable to use any 3-series models. My reverse proxy traffic shows a 429 (Too Many Requests) status. What should I do to resolve this?

[vrdons]

Hello, I am encountering the following error:

All accounts exhausted. Last error: HTTP 403: { "error": { "code": 403, "message": "Verify your account to continue.", "status": "PERMISSION_DENIED" }

Currently, I can use any Gemini 2-series models, but I am unable to use any 3-series models. My reverse proxy traffic shows a 429 (Too Many Requests) status. What should I do to resolve this?

Open antigravity and send some messages, after that you will get verification message. after you will do verification progress