Pure case executor for the loaded corpus.

run/1 dispatches each case against the corpus's declared contract-major facade (the frozen v1 facade or the v2 facade; version-neutral primitive surfaces execute the shared modules) and compares the result to the case-declared expectation. .raw sidecar bytes pass through opaque. Every case result is %{"actual" => ..., "agree" => boolean} for a valid expectation or %{"actual" => ..., "agree" => boolean} for an invalid expectation (agreement = the facade returned {:error, :invalid} exactly). The runner never selects trust, reserves replay, or checks revocation — it exercises the pure facade only.