feat: Implement CRUD API endpoints for core modules

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.

api/package.json

@@ -7,10 +7,12 @@
     "start": "node server.js"
   },
   "dependencies": {
-    "@prisma/client": "^6.7.0",
+    "@prisma/client": "^6.8.2",
     "express": "^4.18.2",
     "node-cron": "^4.0.5",
-    "pg": "^8.8.0",
-    "prisma": "^6.7.0"
+    "pg": "^8.8.0"
+  },
+  "devDependencies": {
+    "prisma": "^6.8.2"
   }
 }