Refactor: Centralize Prisma schema and restrict DB access

This commit refactors the project to use a shared Prisma schema and restricts direct database access to the API service.

Key changes:

- Created a new shared package `core/prisma` containing the Prisma schema, generated client, and types.
- Configured the monorepo to use NPM workspaces, including `core/prisma` and all services.
- Updated all services (`api`, `ui`, `mcp`, `agent`, and the background processing service) to depend on `@empresa/prisma-schema`.
- The API service now imports `PrismaClient` from `@empresa/prisma-schema/client`.
- Other services import only types from `@empresa/prisma-schema`.
- Removed redundant Prisma configurations from `api` and the background processing service.
- Updated the background processing service's `sync-empleados.js` to fetch data via an API call instead of direct database access.
- Updated TypeScript configurations (`tsconfig.base.json` and service-specific ones) to support the new structure and path aliases.
- Updated `README.md` to reflect the new architecture and added convenience scripts for Prisma operations.

This change promotes a single source of truth for data models, reduces code duplication, and improves the overall architecture by centralizing database operations within the API service.

api/prisma/schema.prisma

@@ -1,88 +0,0 @@
-generator client {
-  provider = "prisma-client-js"
-  output   = "generated/client"
-}
-
-datasource db {
-  provider = "postgresql"
-  url      = env("DATABASE_URL")
-}
-
-model Cliente {
-  id            BigInt   @id @default(autoincrement())
-  created_at    DateTime @default(dbgenerated("(now() AT TIME ZONE 'utc')"))
-  updated_at    DateTime @default(dbgenerated("(now() AT TIME ZONE 'utc')")) @updatedAt
-  name          String
-  cedula        BigInt   @unique
-  ubicacion     String   @default(".")
-  grupo_estudio String?
-  empleado      Boolean  @default(false)
-  avatar_url    String?
-  telefono      String?
-  idciat        String?
-
-  asistencias      Asistencia[]
-  tareasRealizadas TareaRealizada[]
-  planillas        Planilla[]
-}
-
-model Planilla {
-  id            BigInt    @id @default(autoincrement())
-  created_at    DateTime  @default(dbgenerated("(now() AT TIME ZONE 'utc')"))
-  updated_at    DateTime  @default(dbgenerated("(now() AT TIME ZONE 'utc')")) @updatedAt
-  fecha_desde   DateTime
-  fecha_hasta   DateTime
-  titulo        String
-  total         Decimal?
-  estado        String    @default("pagado")
-  fecha_anulado DateTime?
-
-  tareasRealizadas TareaRealizada[]
-
-  empleado_id BigInt
-  empleado    Cliente @relation(fields: [empleado_id], references: [id])
-
-
-  creador_id  String? @default(uuid()) @db.Uuid
-  anulador_id String? @db.Uuid
-}
-
-model TareaRealizada {
-  id            BigInt    @id @default(autoincrement())
-  titulo        String
-  precio        Float?
-  estado        String    @default("pendiente")
-  observacion   String?
-  fecha         DateTime
-  created_at    DateTime  @default(dbgenerated("(now() AT TIME ZONE 'utc')"))
-  tipo          String    @default("")
-  fecha_anulado DateTime?
-
-  planilla_id   BigInt?
-  planilla    Planilla? @relation(fields: [planilla_id], references: [id])
-
-  empleado_id BigInt
-  empleado    Cliente @relation(fields: [empleado_id], references: [id])
-
-  creador_id  String  @default(uuid()) @db.Uuid
-  anulador_id String? @db.Uuid
-}
-
-model Asistencia {
-  id            BigInt    @id @default(autoincrement())
-  created_at    DateTime  @default(dbgenerated("(now() AT TIME ZONE 'utc')"))
-  updated_at    DateTime  @default(dbgenerated("(now() AT TIME ZONE 'utc')")) @updatedAt
-  entrada       DateTime? @default(dbgenerated("(now() AT TIME ZONE 'utc')"))
-  salida        DateTime?
-  historial     Json?
-  observacion   String?
-  estado        String?   @default("pendiente")
-  fecha_anulado DateTime?
-
-  empleado_id BigInt
-  empleado    Cliente @relation(fields: [empleado_id], references: [id])
-
-  creador_id    String  @default(uuid()) @db.Uuid
-  modificado_id String? @db.Uuid
-  anulador_id   String? @db.Uuid
-}