feat(ui): add codex intelligence selector

[vincenzopalazzo]

Summary

• Add an Intelligence selector for ChatGPT Codex in the desktop model switch modal
• Persist the selected value to CHATGPT_CODEX_REASONING_EFFORT
• Match backend-supported levels: low, medium, high, and xhigh for known Codex models; fallback to medium/high otherwise
• Add extracted i18n messages for the new labels

Review Notes

• Production-safety review passed (2 clean rounds)
• This reuses the existing ChatGPT Codex provider config path added for reasoning effort; no server/OpenAPI changes needed
• Kept the scope global-config based, matching the current provider implementation

Test plan

• pnpm run lint:check
• pnpm run test:run
• CI passes
• Manual: select ChatGPT Codex in the model switch modal and confirm the Intelligence selector persists to CHATGPT_CODEX_REASONING_EFFORT

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

💡 Codex Review

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Reviewed commit: f4f50ae0de

ℹ️ About Codex in GitHub

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[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 1ce816b6a2

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[DOsinga]

Thanks for the PR! The code looks clean and follows existing patterns well.

One concern: this adds another provider-specific thinking control to the UI, which is already getting fragmented (Claude thinking type/effort/budget, Gemini thinking level, and now Codex intelligence). There was a prior attempt to unify all of these into a single control in #7628 that was abandoned.

Could you have a look at that PR and see if you think that unified approach is the way to go here? It would be great to solve this once for all providers rather than adding another one-off.

[jamadeo]

I believe this is obviated by #9242, which unifies the setting across providers. Feel free to re-open if that PR doesn't address this. Thank you!