Add a reproducible pilot release-candidate gate and handoff bundle

Parent: #93

Depends on: #95

Add a deterministic local release-candidate gate over the verified synthesis kit, plus a bounded handoff bundle containing only versioned artifacts, checksums, runbook references and explicit acceptance status. No remote publication, signing, installer or automatic upload.

Start by reading parent issue #93 and dependency #95, then locate the verified synthesis kit and its existing runbook references. Define the deterministic local release-candidate gate and bounded handoff bundle; done means versioned artifacts, checksums, explicit acceptance status, and no remote publication, signing, installer, or automatic upload.

Written by the indexing model from the issue text.