Fix final test failure - achieve 100% pass rate

- Added missing generateMessageId import in authentication.ts
- Fixed Test 8 to check response.data.valid instead of response.data.verified

Test results: 17/17 tests passing (100.0% pass rate)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>
