Adds Express.js routes and Prisma-based handlers for common database operations (Create, Read, Update, Delete) for the following modules:
- Empleados (subset of Cliente model)
- Asistencias
- Tareas (TareaRealizada model)
- Planillas
Each module's routes are separated into their own files within `api/routes/`. The new routes are registered in `api/server.js`.
Basic error handling, including try-catch blocks and checks for common Prisma errors (e.g., P2025 for record not found, P2003 for foreign key violations), has been implemented in each endpoint.
