[Docs] Add provider qualification checklist

[roomote-roomote]

​Opened on behalf of @mrubens. View the task or mention @roomote-roomote for follow-up asks.

What changed

• Added a reusable qualification checklist for OpenAI-compatible inference providers and gateways.
• Defined the evidence a compatibility report should include across model discovery, streaming, tool calls, multi-turn behavior, limits, and errors.
• Directed provider maintainers to Roomote's issue-first review and contribution process.

Why this change was made

The existing guide explains how operators connect an endpoint, but provider maintainers had no concrete way to demonstrate compatibility or request review. The new guidance makes that path self-service without treating protocol compatibility as endorsement or adding an untested catalog provider.

Impact

Provider maintainers can submit focused, privacy-safe compatibility evidence, while maintainers receive a consistent review packet instead of an unsolicited integration pull request.

Screenshots

[roomote-community]

1 issue outstanding. See task

• apps/docs/providers/inference/openai-compatible.mdx:75-76 Limit the credential-rejection check to endpoints that require bearer authentication.

_{Reviewed adcc351}

[roomote-community]

This makes authentication rejection a requirement for every qualifying endpoint, but this same guide explicitly supports endpoints without an API key (including local servers). Those endpoints cannot reject a missing credential, so they are incorrectly excluded from the checklist. Scope this assertion to endpoints configured to require bearer auth, and allow keyless endpoints to report that authentication is not applicable.