Coastal Timesheet v2 — full feature buildout

Features:
- Copy Previous Week (entries duplication)
- Bulk Approve/Reject (admin workflow)
- Overtime tracking (employee + admin views)
- DayCard component with auto-save
- PDF generation, email notifications
- React + Tailwind frontend, Prisma + PostgreSQL backend
- Docker deployment (3 containers)

backend/prisma/migrations/migration_lock.toml

@@ -0,0 +1 @@
+{"provider":"postgresql"}