fix(security): close remaining SBOM verification gaps

[hyochan]

Summary

• Follow up on the SBOM work in feat(security): per-release SBOM, CRA reporting path, and supply-chain docs #318, fix(security): make the SBOM workflow able to describe any release tag #319, and fix(security): repair SBOM automation and accuracy #332 by filling the remaining post-merge verification and recovery gaps from SBOM system: automation never fires, extraction is inaccurate, audit tooling is broken #323.
• Repair the legacy react-native-iap-16.3.0 SBOM only when its exact published SHA-256 digest is still present.
• Verify existing release assets against release identity, tag commit, generator commit, GitHub digest, dependency graph, and exact main workflow provenance before preserving them.

Refs #323

Why this follow-up is needed

• feat(security): per-release SBOM, CRA reporting path, and supply-chain docs #318 introduced per-release CycloneDX SBOMs and provenance attestations.
• fix(security): make the SBOM workflow able to describe any release tag #319 made the current generator able to describe historical release tags.
• fix(security): repair SBOM automation and accuracy #332 wired release dispatch and backfill, corrected dependency extraction, and repaired the inaccurate Google 3.3.0 asset.

Post-merge verification found one legacy React Native asset that predates the generator-commit field, plus fail-open paths where an existing or concurrently replaced asset could be preserved without proving it came from the exact main workflow. This PR fills those remaining gaps instead of broadening the repair scope.

Changes

Published asset verification

• Add a reusable verifier for release identity, release commit, generator commit, GitHub SHA-256 digest, CycloneDX structure, dependency reachability, and path/secret leakage.
• Require the exact sbom.yml@refs/heads/main certificate identity and a GitHub-hosted runner.
• Restrict publication to workflow_dispatch runs on the repository default branch and remove the incompatible release-event lane.

Guarded recovery

• Add the exact legacy digest for react-native-iap-16.3.0 alongside the existing Google 3.3.0 repair guard.
• Verify a non-legacy canonical asset before cleaning any staged replacement.
• Retain the staged marker when the canonical asset changes during repair so the next main-branch run must reconcile it instead of silently preserving unverified state.

Audit and documentation

• Audit every newest component SBOM with fail-fast content, digest, schema, and provenance checks.
• Document exact-main workflow verification in the repository and docs site.

Verification

• 78 release, provenance, SBOM, and security automation tests
• 45 documentation audit tests
• bun run audit:docs
• bun run audit:parity
• bun run audit:release-state
• Docs typecheck, lint, format check, and production build
• actionlint .github/workflows/sbom.yml
• Prettier and git diff --check
• Production docs bundle renders the exact-main attestation command with no new console errors
• Fresh public release scan selects only react-native-iap-16.3.0 for the guarded repair

Preview

The rendered SBOM documentation preview is attached in the PR conversation.

[hyochan]

Preview

Rendered production documentation showing the exact-main attestation command:

sbom-preview.mp4