Summary

/claim #71

Adds focused Vitest coverage for the cron plugin utility helpers:

• verifies valid cron expressions can be parsed
• verifies invalid cron expressions throw
• verifies next execution time calculation for a same-day schedule
• verifies next execution time rolls over to the following day after the scheduled time has passed

Validation

• pnpm exec vitest run plugins/cron/utils.test.ts

Notes

I also ran the full test suite locally with npx vitest run. The new cron tests passed, but the full suite currently has unrelated pre-existing failures in src/rls/index.test.ts where RLS policy injection expectations receive unchanged SQL.