feat: Initialize backend with NestJS framework and serial communication

- Added package.json for backend dependencies and scripts.
- Implemented basic AppController and AppService with a simple "Hello World!" endpoint.
- Created SerialModule for handling serial communication with the Pico.
- Developed SerialController and SerialService to manage serial ports and commands.
- Implemented event streaming for serial data.
- Added Jest tests for AppController and e2e tests for the application.
- Set up TypeScript configuration for the backend.
- Created frontend SendBox component for sending commands to the backend.
- Established Pico firmware for controlling a stepper motor via serial commands.
- Documented project structure and usage in README files.

backend/test/app.e2e-spec.ts

@@ -0,0 +1,25 @@
+import { Test, TestingModule } from '@nestjs/testing';
+import { INestApplication } from '@nestjs/common';
+import * as request from 'supertest';
+import { App } from 'supertest/types';
+import { AppModule } from './../src/app.module';
+
+describe('AppController (e2e)', () => {
+  let app: INestApplication<App>;
+
+  beforeEach(async () => {
+    const moduleFixture: TestingModule = await Test.createTestingModule({
+      imports: [AppModule],
+    }).compile();
+
+    app = moduleFixture.createNestApplication();
+    await app.init();
+  });
+
+  it('/ (GET)', () => {
+    return request(app.getHttpServer())
+      .get('/')
+      .expect(200)
+      .expect('Hello World!');
+  });
+});

backend/test/jest-e2e.json

@@ -0,0 +1,9 @@
+{
+  "moduleFileExtensions": ["js", "json", "ts"],
+  "rootDir": ".",
+  "testEnvironment": "node",
+  "testRegex": ".e2e-spec.ts$",
+  "transform": {
+    "^.+\\.(t|j)s$": "ts-jest"
+  }
+}