first commit backend

backend/src/app.ts

@@ -0,0 +1,16 @@
+import express from 'express';
+
+const app = express();
+const port = process.env.PORT ?? 3000;
+
+app.use(express.json());
+
+app.get('/', (_req, res) => {
+  res.json({
+    message: 'API funcionando con Express + TypeScript + TSX',
+  });
+});
+
+app.listen(port, () => {
+  console.log(`Servidor corriendo en http://localhost:${port}`);
+});