refactor(release): remove unreachable DER parser guards

[mldangelo-oai]

Summary

Remove unreachable DER parser checks and a test that snapshots their source text.

Changes

• Rely on the existing DER element parser, which already guarantees cursor advancement and enforces the parent boundary.
• Delete the source-regex test while retaining behavioral malformed-certificate and provenance coverage.

Testing

• bun test tests-ts/release-automation.test.ts tests-ts/package-provenance.test.ts --timeout 30000 — passed.
• pnpm run types — passed.
• prettier --check scripts/release-automation.mjs tests-ts/release-automation.test.ts — passed.
• git diff --check — passed.

Risk and rollout

Every accepted DER element consumes its tag and length bytes, and the parser rejects elements extending beyond their parent. Existing malformed-certificate, signing, and package-provenance tests continue to exercise the actual verification behavior.

Public disclosure review

• No customer, partner, prospect, or user identities, data, or identifying details are included.
• No credentials, personal data, private source, scan findings, or nonpublic links or tickets are included.
• I reviewed the branch name, title, description, commits, changes, comments, logs, screenshots, attachments, and links for public disclosure.

[mldangelo-oai]

@codex review

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. Keep them coming!

Reviewed commit: 649a265650

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[chatgpt-codex-connector]

Security review completed. No security issues were found in this pull request.

Reviewed commit: 649a265650

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[zcrab-oai]

Looks good. Removes unreachable DER parser guards while preserving malformed certificate and release-signing verification.