refactor: update code style and improve ESLint rules for better consistency

src/main.ts

@@ -1,8 +1,8 @@
-import { NestFactory } from '@nestjs/core';
-import { AppModule } from './app.module';
+import { NestFactory } from "@nestjs/core";
+import { AppModule } from "./app.module";
 
 async function bootstrap() {
-  const app = await NestFactory.create(AppModule);
-  await app.listen(process.env.PORT ?? 3000);
+    const app = await NestFactory.create(AppModule);
+    await app.listen(process.env.PORT ?? 3000);
 }
-bootstrap();
+void bootstrap();