Create timestamped checkpoints of the supported local job signals before and after revisions, proof approval or release. The log is intentionally transparent about its limits: local storage is convenient, not immutable.
A snapshot records which supported signals exist, selected headline fields and—when Web Crypto is available—a SHA-256 fingerprint of the normalized snapshot JSON. It never includes image bytes.
When HTTPS Web Crypto is available, the snapshot JSON receives a SHA-256 fingerprint. Recomputing the same normalized snapshot should produce the same fingerprint, but localStorage itself can still be edited or deleted.
Capture before and after a major revision, proof approval or production release. The label and note make the chronology understandable when the raw signals are later exported.
Browser storage is convenient but not archival. Export the audit log and release packet into the job’s controlled records when traceability matters.