refactor: isolate SSE setup

api/server.js

@@ -2,6 +2,7 @@ import express from 'express';
 import { PrismaClient } from './prisma/generated/client/index.js';
 import { Decimal } from '@prisma/client/runtime/library.js';
 import cors from 'cors';
+import { registerSse } from './sse/index.js';
 
 // Import new routers
 import empleadosRouter from './routes/empleados/empleados.js';
@@ -48,6 +49,9 @@ app.use(cors({
   origin: ['http://localhost:5173', 'https://planilla.interno.com'],
   credentials: true
 }));
+
+// --------- Server Sent Events setup ---------
+registerSse(app);
 // Mount new routers
 app.use('/api/empleados', empleadosRouter);
 app.use('/api/asistencias', asistenciasRouter);