Publish an API catalog for automated API discovery (RFC 9727)

## Problem API Catalog not found at `/.well-known/api-catalog`. ## Goal Enable automated API discovery so agents can find and understand available APIs. ## Fix Create `/.well-known/api-catalog` returning `application/linkset+json` with a `linkset` array. Each entry should include: - `anchor` — the API URL - `service-desc` — link to OpenAPI spec - `service-doc` — link to documentation - `status` — link to health endpoint See RFC 9727 Appendix A for a full example. ## References - Skill: https://isitagentready.com/.well-known/agent-skills/api-catalog/SKILL.md - Docs: https://www.rfc-editor.org/rfc/rfc9727 - Docs: https://www.rfc-editor.org/rfc/rfc9264