feat(provider): add data residency header support for OpenAI Enterprise

[DusKing1]

Issue for this PR

No existing issue — this addresses a gap in OpenAI Enterprise support for non-US regions using Codex OAuth.

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

Adds the x-openai-internal-codex-residency HTTP header to OpenAI Codex provider requests in packages/opencode/src/plugin/codex.ts.

Problem: OpenAI Enterprise workspaces with US data residency reject Codex API requests from non-US regions with 401 "Workspace is not authorized in this region". OpenCode's Codex auth plugin shares the identical OAuth flow, client ID, and endpoint as OpenAI's own Codex CLI — but is missing this one header.

Fix: Read enforce_residency from provider options and set x-openai-internal-codex-residency in the chat.headers hook. This mirrors exactly how Codex CLI handles it in codex-rs/core/src/default_client.rs. Users configure it via opencode.json:

{
  "provider": {
    "openai": {
      "options": {
        "enforce_residency": "us"
      }
    }
  }
}

The provider options schema already uses .catchall(z.any()), so no schema changes are needed.

How did you verify your code works?

• Verified the header is added to outgoing requests when enforce_residency is set in provider config
• Confirmed the header is NOT added when the option is absent (no impact on non-Enterprise users)
• Cross-referenced with Codex CLI source to ensure header name and value match exactly

Screenshots / recordings

N/A — backend-only change, no UI impact.

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR

[github-actions]

Hey! Your PR title feat(plugin/codex): add data residency header support for OpenAI Enterprise doesn't follow conventional commit format.

Please update it to start with one of:

• feat: or feat(scope): new feature
• fix: or fix(scope): bug fix
• docs: or docs(scope): documentation changes
• chore: or chore(scope): maintenance tasks
• refactor: or refactor(scope): code refactoring
• test: or test(scope): adding or updating tests

Where scope is the package name (e.g., app, desktop, opencode).

See CONTRIBUTING.md for details.

[github-actions]

Thanks for updating your PR! It now meets our contributing guidelines. 👍

[DusKing1]

I verified this change locally and it works as expected. After configuring enforce_residency for the OpenAI provider, requests consistently include the x-openai-internal-codex-residency header.

[GreyElec]

it looks good and looking forward to see this in the official version

[rekram1-node]

Automated PR Cleanup

Thank you for contributing to opencode.

Due to the high volume of PRs from users and AI agents, we periodically close older PRs using automated criteria so maintainers can focus review time on the most active and community-supported contributions.

This PR was closed because it matched the following cleanup criteria:

• The PR was created more than 1 month ago
• The PR had fewer than 2 positive reactions
• Positive reactions are counted as thumbs-up, heart, celebration, or rocket reactions on the PR

PRs created within the last month are not affected by this cleanup.

If you believe this PR was closed incorrectly, or if you are still actively working on it, please leave a comment explaining why it should be reopened. A maintainer can review and reopen it if appropriate.

Thanks again for taking the time to contribute.