SIGMA PROOFKIT: Document files now. Verify them later.

I built SIGMA PROOFKIT around a simple problem: saving files does not prove that the copies you look at later are unchanged from the ones you originally documented. ProofKit creates a documented baseline using preservation copies, SHA-256 hashes, evidence manifests, and PDF records, then lets you verify a later file set against that baseline. One design principle was important from the start: don’t claim more than the evidence proves. A matching hash can show that file contents match, but it cannot establish authorship, truth, event time, or what happened before the baseline was created. I’d especially value feedback from people working in security, compliance, investigations, risk, and document control.