Initialize NestJS backend with basic structure, Biome setup, and essential configurations

backend/src/app.controller.ts

@@ -0,0 +1,12 @@
+import { Controller, Get } from '@nestjs/common';
+import { AppService } from './app.service';
+
+@Controller()
+export class AppController {
+  constructor(private readonly appService: AppService) {}
+
+  @Get()
+  getHello(): string {
+    return this.appService.getHello();
+  }
+}