Castlabs c2pa-python 0.37.12.dev4 (VSI)

castlabs-vsi-release:0.37.12.dev4

Castlabs c2pa-python 0.37.12.dev4 immutable prerelease. Conformance Program 0.2 / C2PA 2.4 candidate (successor to the published dev3; crJSON 2.4 conformance): live-video VSI merged with contentauth main 6c92bc32, single-file fMP4 Merkle and TFRA fixes, caller-controlled validation time and purpose-scoped trust. See the attached schema-2 evidence and SHA-256 sidecars.