feat: integrate Tailwind CSS for improved styling and layout

- Added Tailwind CSS and its Vite plugin to the frontend project.
- Updated App.svelte to enhance UI with Tailwind classes, including a new layout for the serial monitor and command tester.
- Improved logging functionality by increasing log history and adding more detailed log messages.
- Refactored SendBox.svelte for consistent styling with Tailwind.
- Enhanced Pico firmware to support structured event logging and command parsing.
- Updated README_PICO_SERIAL.md to provide comprehensive documentation on serial communication and backend integration.
- Added .dockerignore to optimize Docker builds by excluding unnecessary files.

backend/src/main.ts

@@ -1,8 +1,29 @@
 import { NestFactory } from '@nestjs/core';
 import { AppModule } from './app.module';
+import { NestExpressApplication } from '@nestjs/platform-express';
+import { join } from 'path';
 
 async function bootstrap() {
-  const app = await NestFactory.create(AppModule);
-  await app.listen(process.env.PORT ?? 3000);
+  const app = await NestFactory.create<NestExpressApplication>(AppModule, {
+    bufferLogs: true,
+  });
+
+  // Serve static frontend (built assets copied to /app/public in container)
+  const publicDir = join(process.cwd(), 'public');
+  app.useStaticAssets(publicDir);
+
+  // Basic health endpoint
+  app.getHttpAdapter().get('/healthz', (_req: any, res: any) => {
+    res.json({ ok: true, ts: Date.now() });
+  });
+
+  const port = Number(process.env.PORT || 3000);
+  await app.listen(port);
+  // eslint-disable-next-line no-console
+  console.log(`[bootstrap] Listening on :${port}`);
 }
-bootstrap();
+bootstrap().catch((e) => {
+  // eslint-disable-next-line no-console
+  console.error('Fatal bootstrap error', e);
+  process.exit(1);
+});