compass-a2a-runner: Offline A2A FAIR Signposting benchmark runner for Compass

compass-a2a-runner is an offline, apple-to-apple benchmark runner for assessing how well the Compass validator performs on a curated subset of the A2A FAIR Signposting recipes. It replays harvested HTTP response header fixtures (primarily RFC 8288 Link headers), converts them into a WebLink model, and validates them with Compass against scenario-specific expectations (relations and expected issues). Scope note: This benchmark currently covers only the HTTP scenarios. Inline HTML signposting is intentionally not included yet, because that would primarily benchmark HTML-to-WebLink parsing rather than Compass validation (which operates on the WebLink model). Network-based behaviors (dereferencing, conneg, remote Link Sets) are out of scope.