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.

frontend/vite.config.ts

@@ -4,4 +4,14 @@ import { svelte } from '@sveltejs/vite-plugin-svelte'
 // https://vite.dev/config/
 export default defineConfig({
   plugins: [svelte()],
+  server: {
+    proxy: {
+      // forward serial API calls (including SSE) to backend running on :3000
+      '/serial': {
+        target: 'http://localhost:3000',
+        changeOrigin: true,
+        ws: false,
+      },
+    },
+  },
 })