Request for vouch: native Cline API and ClinePass providers

[wtergan]

I would like to contribute native support for both Cline billing routes. The implementation builds on #4586, resolves its outstanding review findings, and adds a separate cline-api usage-credit provider alongside ClinePass.

The branch includes provider-scoped credentials, onboarding/login integration, curated catalogs, wire-ID separation, reasoning compatibility, regression tests, and package documentation. Local verification completed with 443 catalog tests and 2,828 AI tests passing.

I initially opened #5169 before noticing the vouch requirement; it was automatically closed. The branch remains available and has since incorporated the automated review fix for asynchronous Cline CLI credential reads.

Could a maintainer please review this contribution proposal and, if appropriate, vouch @wtergan so I can reopen or resubmit the PR?