Handle Cloudflare AI Gateway responses for codex models

[jameskyle]

Summary

• Route Cloudflare AI Gateway requests to namespace base URLs and force /responses for response-only codex/GPT models so they work through the gateway
• Strip Authorization when cf-aig-authorization is present (or gateway token configured) and preserve it otherwise via shared fetch to avoid auth errors while keeping upstream keys usable
• Add provider tests covering gateway Authorization handling and ignore local log/build artifacts

Testing

• bun turbo typecheck

[github-actions]

Closing this pull request because it has had no updates for more than 60 days. If you plan to continue working on it, feel free to reopen or open a new PR.

[yckbilly1929]

should we re-open this issue? I still struggle to use opencode with Cloudflare AI Gateway gpt-5.3-codex, and does not find any example to successfuly use it.

I have tried to follow the documentation and set the three environment variables: [CLOUDFLARE_ACCOUNT_ID, CLOUDFLARE_GATEWAY_ID, CLOUDFLARE_API_TOKEN].

But when i run it, it shows this error message:
Error: You didn't provide an API key. You need to provide your API key in an Authorization header using Bearer auth (i.e. Authorization: Bearer YOUR_KEY), or as the password field (with blank username) if you're accessing the API from your browser and are prompted for a username and password. You can obtain an API key from https://platform.openai.com/account/api-keys.
which seems to be the issue that the header cf-aig-authorization is not propagated.

And I've tried to customize the provider with "@ai-sdk/openai" but in vein.