#509 Tests: wire 5 orphaned test files into package.json scripts

[Anonymous]

Originally created by: Redo-San

These 5 committed test files exist but are referenced from nowhere in package.json, so they never run in CI.

File	Lines	Self-contained?
cli/tests/voice_audio_embed_test.js	573	yes — node:test + vm loader, no server
cli/tests/voice_c2pa_audio_hash_test.js	222	yes — same pattern
cli/tests/e2e/e2e_did_sign_test.js	287	starts its own server via ./e2e_helpers, PORT 9873
cli/tests/e2e/e2e_fingerprint_hashes_test.js	156	same
cli/tests/e2e/e2e_metadata_download_test.js	159	same

Change

Append the first two to scripts["test:voice"] and the last three to scripts["test:e2e-all"].

Acceptance criteria

• [ ] npm run test:voice now runs 18 files (currently 16).
• [ ] node --test cli/tests/voice_audio_embed_test.js exits 0.
• [ ] node --test cli/tests/e2e/e2e_did_sign_test.js exits 0.
• [ ] npm run test:quick unaffected.