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/migrations/20250530222717_init/migration.sql

@@ -1,18 +0,0 @@
--- AlterTable
-ALTER TABLE "Asistencia" ALTER COLUMN "created_at" SET DEFAULT (now() AT TIME ZONE 'utc'),
-ALTER COLUMN "updated_at" SET DEFAULT (now() AT TIME ZONE 'utc'),
-ALTER COLUMN "entrada" SET DEFAULT (now() AT TIME ZONE 'utc');
-
--- AlterTable
-ALTER TABLE "Cliente" ALTER COLUMN "created_at" SET DEFAULT (now() AT TIME ZONE 'utc'),
-ALTER COLUMN "updated_at" SET DEFAULT (now() AT TIME ZONE 'utc');
-
--- AlterTable
-ALTER TABLE "Planilla" ALTER COLUMN "created_at" SET DEFAULT (now() AT TIME ZONE 'utc'),
-ALTER COLUMN "updated_at" SET DEFAULT (now() AT TIME ZONE 'utc');
-
--- AlterTable
-ALTER TABLE "TareaRealizada" ALTER COLUMN "created_at" SET DEFAULT (now() AT TIME ZONE 'utc');
-
--- AddForeignKey
-ALTER TABLE "TareaRealizada" ADD CONSTRAINT "TareaRealizada_planilla_id_fkey" FOREIGN KEY ("planilla_id") REFERENCES "Planilla"("id") ON DELETE SET NULL ON UPDATE CASCADE;