Default Bootstrap theme to dark mode

- Change default theme from light to dark for first-time visitors
- Fix Alpine reactive theme toggle so icons and data-bs-theme update correctly
- Remove hardcoded bg-light classes that prevented dark mode from applying
- Fix broken duplicate Bootstrap bundle import in app.js

resources/views/livewire/auth/login.blade.php

@@ -29,7 +29,7 @@ new #[Layout('components.layouts.guest')] class extends Component {
 }
 ?>
 
-<div class="min-vh-100 d-flex align-items-center justify-content-center bg-light">
+<div class="min-vh-100 d-flex align-items-center justify-content-center">
     <div class="card shadow-sm" style="width: 100%; max-width: 420px;">
         <div class="card-body p-4">
             <div class="text-center mb-4">