Update formatting rules to enforce consistent tab-based indentation across the backend

backend/test/app.e2e-spec.ts

@@ -1,25 +1,25 @@
-import { Test, TestingModule } from '@nestjs/testing';
-import { INestApplication } from '@nestjs/common';
-import request from 'supertest';
-import { App } from 'supertest/types';
-import { AppModule } from './../src/app.module';
+import { Test, TestingModule } from "@nestjs/testing";
+import { INestApplication } from "@nestjs/common";
+import request from "supertest";
+import { App } from "supertest/types";
+import { AppModule } from "../src/app.module";
 
-describe('AppController (e2e)', () => {
-  let app: INestApplication<App>;
+describe("AppController (e2e)", () => {
+	let app: INestApplication<App>;
 
-  beforeEach(async () => {
-    const moduleFixture: TestingModule = await Test.createTestingModule({
-      imports: [AppModule],
-    }).compile();
+	beforeEach(async () => {
+		const moduleFixture: TestingModule = await Test.createTestingModule({
+			imports: [AppModule],
+		}).compile();
 
-    app = moduleFixture.createNestApplication();
-    await app.init();
-  });
+		app = moduleFixture.createNestApplication();
+		await app.init();
+	});
 
-  it('/ (GET)', () => {
-    return request(app.getHttpServer())
-      .get('/')
-      .expect(200)
-      .expect('Hello World!');
-  });
+	it("/ (GET)", () => {
+		return request(app.getHttpServer())
+			.get("/")
+			.expect(200)
+			.expect("Hello World!");
+	});
 });