Redirect landing to login, add registration toggle

Changes:
- Landing page (/) now redirects to /login
- Added 'Enable User Registration' setting (off by default)
- Created CheckRegistrationEnabled middleware
- Registration routes blocked when setting is disabled
- Admin can toggle registration in Settings > System

src/app/Filament/Pages/Settings.php

@@ -31,6 +31,7 @@ public function mount(): void
         $siteDescription = Setting::get('site_description');
         $contactEmail = Setting::get('contact_email');
         $maintenanceMode = Setting::get('maintenance_mode', false);
+        $enableRegistration = Setting::get('enable_registration', false);
 
         $this->form->fill([
             'site_name' => is_string($siteName) ? $siteName : config('app.name'),
@@ -41,6 +42,7 @@ public function mount(): void
             'site_description' => is_string($siteDescription) || is_null($siteDescription) ? $siteDescription : '',
             'contact_email' => is_string($contactEmail) || is_null($contactEmail) ? $contactEmail : '',
             'maintenance_mode' => is_bool($maintenanceMode) ? $maintenanceMode : false,
+            'enable_registration' => is_bool($enableRegistration) ? $enableRegistration : false,
         ]);
     }
 
@@ -87,6 +89,10 @@ public function form(Form $form): Form
 
                 Forms\Components\Section::make('System')
                     ->schema([
+                        Forms\Components\Toggle::make('enable_registration')
+                            ->label('Enable User Registration')
+                            ->helperText('Allow new users to register. When disabled, only admins can create users.'),
+                        
                         Forms\Components\Toggle::make('maintenance_mode')
                             ->label('Maintenance Mode')
                             ->helperText('Enable to put the site in maintenance mode'),
@@ -116,6 +122,7 @@ public function save(): void
         Setting::set('site_description', $data['site_description'] ?? '');
         Setting::set('contact_email', $data['contact_email'] ?? '');
         Setting::set('maintenance_mode', $data['maintenance_mode'] ?? false, 'boolean');
+        Setting::set('enable_registration', $data['enable_registration'] ?? false, 'boolean');
 
         Notification::make()
             ->title('Settings saved successfully')