GitHub REST API example

The validation project at validation/github/ (in the source tree) models a 22-endpoint slice of GitHub’s REST API. Highlights:

• Two actors (user + admin PAT) with the same auth strategy but different scopes
• Header-based pagination via Link: <...>; rel="next"
• Deep dependency chain: repo → branch → content → pull → merge

This was one of the three Phase 0 validation APIs; the findings document at validation/github/findings.md (local-only) details the schema gaps that informed the spec.

Full annotated walkthrough is part of Phase 2 documentation.