Align CI/test setup with SimpleDoc and expand coverage

[dutifulbob]

Summary

• switch CI Node runtime to 24 with check-latest enabled
• simplify test script to Node 24 glob runner
• add/expand tests for ttl parsing, sessions new help surface, ttl normalization edge cases, and explicit 5-agent registry coverage
• remove module-mock-dependent session test path so tests run without experimental flags

Validation

• npm run typecheck
• npm run lint
• npm run format:check
• npm run build
• npm test