fix: Configure Vite for nginx reverse proxy

- Add --host flag to bind to all interfaces
- Add __VITE_ADDITIONAL_SERVER_ALLOWED_HOSTS env var for external domain
- Configure allowedHosts in vite.config.ts
- Remove duplicate vite.config.js (was overriding .ts config)
- Enable IPv4 binding for nginx proxy compatibility

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

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

admin-ui/package.json

@@ -5,7 +5,7 @@
   "private": true,
   "type": "module",
   "scripts": {
-    "dev": "vite",
+    "dev": "__VITE_ADDITIONAL_SERVER_ALLOWED_HOSTS=dss.overbits.luz.uy vite --host",
     "build": "tsc && vite build",
     "preview": "vite preview",
     "test": "vitest",