- Add reminders to Prisma schema (Reminder model, TaskReminder relation)
- Add /api/reminders endpoint and cron send-reminders.ts script
- Add reminder fields to NewTaskModal and EditTaskModal components
- Fix reminder datetime serialization: use toISOString().slice(0,16) for
UTC-safe YYYY-MM-DDTHH:mm format compatible with datetime-local inputs
- Update Dockerfile to install tsx for cron container
- Add AGENTS.md with project conventions
- Update docker-compose.yml with cron service and build context
- Migrate due_date/next_occurrence columns from TIMESTAMPTZ to DATE
- Update serializeRow() to distinguish DATE vs TIMESTAMPTZ serialization
- Simplify frontend date parsing (no more timezone workarounds)
- Add Vitest + Testing Library test infrastructure
- Add initial date parsing/formatting unit tests
- Update package.json with dev dependencies (vitest, testing-library, jsdom)
