The Thread conformance suite

A standard is only real if it can be checked without the reference browser. This crate is that check: point it at a corpus of worlds (a directory of world.jsons) and it reports, browser-independently, whether they honour the spec — manifests validate, worlds are enterable, links are well-formed, and the constellation hangs together. It's the artifact that lets a third party prove their worlds (or their own engine's output) conform, with zero contact.

Clauses are either Error (a real conformance violation — fails the suite) or Warn (a quality signal that doesn't break interop — reported, but the suite still passes). [run] returns a [Report]; [Report::passed] is true when no Error clause failed.