test: authenticate LinxISA 0.58.1 model evidence

[zhoubot]

Summary

• authenticate complete LinxISA 0.58.1 codec authority and hosted regeneration
• require canonical release-strict artifacts, fresh result memory, and exact consumer/golden pairwise proof
• bind stored evidence to canonical suite, source, QEMU, compiler, model, ELF, manifest, and result hashes

Verification

• independent review: PASS (0 Critical, 0 Important)
• model CTest: 12/12
• root strict units: 50/50
• canonical release-strict suite: 7/7
• codec freshness: 765 forms / 2661 fields / 3401 pieces / 780 constraints

The existing linxisa-v0.58.1 tag is immutable and is not moved.