feat: implement adaptive multi-pane mailbox with utilities and security gates

- Added fully responsive 3-pane layout for Mailbox
- Integrated global cinematic Toast system in app shell
- Implemented Copy to Clipboard and QR Code modal utilities
- Added diverse mock email data for premium demonstration
- Implemented security gates for custom mailboxes and attachments
- Fixed critical 500 error for orphaned email selection
- Refined landing page hero CTA text

routes/web.php

@@ -8,6 +8,7 @@ use Illuminate\Support\Facades\Route;
 use Laravel\Fortify\Features;
 
 Route::get('/', \App\Livewire\LandingPage::class)->name('home');
+Route::get('/mailbox', \App\Livewire\Mailbox::class)->name('mailbox');
 Route::get('/privacy-policy', \App\Livewire\PrivacyPolicy::class)->name('privacy');
 
 Route::view('dashboard', 'dashboard')