fix: remove all dark mode styles from shared UI components

Stripped dark: classes from Input, Textarea, Button, and InputField
components. These were causing black/dark backgrounds in modals and
forms across all apps (backoffice, gacha, dimentorin, etc).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/backoffice/src/app/404.tsx

@@ -2,13 +2,13 @@ import { Link } from 'react-router-dom';
 
 export default function NotFoundPage() {
   return (
-    <div className="min-h-screen flex items-center justify-center bg-gray-50 dark:bg-gray-950">
+    <div className="min-h-screen flex items-center justify-center bg-gray-50">
       <div className="text-center">
         <h1 className="text-9xl font-bold text-gray-200 mb-4">404</h1>
-        <h2 className="text-3xl font-semibold text-gray-900 dark:text-gray-300 mb-4">
+        <h2 className="text-3xl font-semibold text-gray-900 mb-4">
           Page Not Found
         </h2>
-        <p className="text-gray-600 dark:text-gray-400 mb-8">
+        <p className="text-gray-600 mb-8">
           The page you are looking for doesn't exist or has been moved.
         </p>
         <Link