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.

frontend/vite.config.ts

@@ -1,9 +1,13 @@
 import { defineConfig } from 'vite'
 import { svelte } from '@sveltejs/vite-plugin-svelte'
+import tailwindcss from '@tailwindcss/vite'
 
 // https://vite.dev/config/
 export default defineConfig({
-  plugins: [svelte()],
+  plugins: [
+    svelte(),
+    tailwindcss(),
+  ],
   server: {
     proxy: {
       // forward serial API calls (including SSE) to backend running on :3000