fix(web): add @tailwindcss/vite plugin to web config

The web version was missing the Tailwind CSS Vite plugin, causing
CSS to not load at all. This adds the same plugin configuration
that exists in the tauri version.

Fixes #121

web/vite.config.ts

@@ -1,9 +1,10 @@
 import path from 'node:path';
 import react from '@vitejs/plugin-react';
+import tailwindcss from '@tailwindcss/vite';
 import { defineConfig } from 'vite';
 
 export default defineConfig({
-  plugins: [react()],
+  plugins: [react(), tailwindcss()],
   resolve: {
     alias: {
       '@': path.resolve(__dirname, '../app/src'),