Prove generated redline accept/reject reversibility

[JSv4]

Summary

• define an embeddable redline reversibility proof contract with deterministic evidence
• accept/reject generated revision families across document stories and compare them with the intended final/baseline documents
• distinguish modeled semantic equality, exact package equality, and conservative unknown residual differences
• report the first divergent part/anchor and only the revision IDs actually correlated with that location
• cover pre-existing revisions, moves, formatting, lists, tables, sections, headers/footers, notes, comments, bookmarks, and multi-author cases
• consume [Verify] Add a comprehensive deliverable validator #463's shared package delta and recoverable-exception boundary, with bounded revision work and fail-closed live-inventory enforcement

Stack

This draft is based on agent/issue-463-deliverable-verification (PR #496), exact head 3e722c38, which is green and includes the corrected #493 foundation.

Verification

• 131 passed / 0 failed / 0 skipped in the final Release dependency-stack run
• 20 passed / 0 failed / 0 skipped in the focused redline-proof run
• git diff --check passes
• independent post-[Verify] Add a comprehensive deliverable validator #463 review approved with no remaining blocker, high, or medium findings
• review fixes cover shared package comparison, cancellation/fatal propagation, exact surviving-pre-existing evidence, and manifest-plus-live revision budgets

Viewable local evidence is retained at /tmp/docxodus-464-artifacts/index.html, including the complete post-#463 patch, final TRXs, checksums, and useful review-blocked green snapshots.

Closes #464