seals: re-mint 374 green specs as v2 so frontier can reuse them (step 4 of #8095) #8116

Problem

No seal on master is v2 yet, so t27c frontier reuses nothing and CI has nothing to skip. Part of step 4 of #8095.

Spec

specs/verified/seal_identity.t27: a seal is reusable when its five parts are recorded and equal. Re-mint, with t27c seal --save from #8110, every spec whose seal already matches its text with all tests passing (374 specs).

Tests

t27c frontier before: reused 2 of 1712. After: reused 297 of 1712 (173 permille). Every re-minted seal is seal_schema 2; t27c seal --save re-ran each spec's four gens and its tests, and none failed.

Acceptance

The v2 seals are on master; the frontier line in CI (#8095 step 4) reads a non-zero reused share.

User Scenarios

• Given the master branch has no v2 seals, when running t27c frontier, then it reuses only 2 of 1712 specs
• Given 374 specs have matching seals with all tests passing, when re-minting with t27c seal --save, then each spec gets a v2 seal with seal_schema 2
• Given v2 seals are on master, when running t27c frontier in CI, then it reports a non-zero reused share (297 of 1712, 173 permille)

Requirements

FR-001: The tool t27c seal --save MUST re-mint seals for all 374 specs whose current seal matches their text with all tests passing
FR-002: Every re-minted seal MUST have seal_schema version 2
FR-003: The re-minting process MUST re-run each spec's four gens and its tests, and none MUST fail
FR-004: The new seal_identity.t27 spec MUST define when a seal is reusable (five parts recorded and equal)

Success Criteria

• t27c frontier reports reused 297 of 1712 specs (173 permille) exit 0
• All 374 re-minted specs have seal_schema 2 exit 0
• t27c seal --save completes with zero test failures across all re-minted specs exit 0
• specs/verified/seal_identity.t27 exists and defines seal reusability exit 0

Boundary

• specs/verified/seal_identity.t27
• specs/verified/reuse.t27
• specs/tools/tri/seals.t27
• specs/verified/frontier.t27
• cli/tri/src/seals.rs