Fix build failure by adding astro-icon integration

The build was failing with "Rollup failed to resolve import virtual:astro-icon" because the astro-icon package requires its integration to be registered in astro.config.mjs to create the virtual module.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: DorianZheng

astro.config.mjs

@@ -1,8 +1,10 @@
 // @ts-check
 import { defineConfig } from 'astro/config';
+import icon from 'astro-icon';
 
 // https://astro.build/config
 export default defineConfig({
   site: 'https://boxlite-labs.github.io',
   base: '/website',
+  integrations: [icon()],
 });