Prove release publishers in dedicated disposable repositories

[rldyourmnd]

Parent: #127.

Both release-supply-chain variants remain typed blocked. Honest proof creates real tags/releases; the attested variant also writes an irreversible Sigstore transparency-log entry. The ci-workflows repository is not a safe disposable target.

Acceptance criteria:

• use dedicated disposable public/private repositories with no consumers or protected project history
• call each real reusable with the exact plan-appropriate permissions and protected environment
• publish unique tag/release/package state, verify assets/checksums/immutability, and clean all reversible state
• explicitly retain the attestation transparency-log write as irreversible durable evidence
• do not disable publish, provenance, SBOM, attestation, signing, authorization, or promotion jobs
• reject skipped/false-green evidence and record exact current digests and run URLs