E31 Byzantine Governance Proof Fabric (proofs + recomputed quorum + non-authorization)

Clean-room result: VALID (?/7 checks). Invariants 0 all-hold=True; attacks 0 all-contained=True; tests passed=7.

Verify: python3 verify_e31.py . · REPRODUCE.txt · manifest.json

Honest: same-project clean room, NOT third-party verification; no production claim.