feat: VivesPOS landing on Winter CMS 1.2 — theme + plugin + Dockerfile

- Base: wintercms/winter branch 1.2 (full framework)
- Theme vivespos: Canvas 7 + Bootstrap 5 CDN, custom CSS
- Layout: deferred GTM/GA4 tracking, JSON-LD SoftwareApplication
- Partials: hero (offline-first), features, modes (offline/nube toggle),
  screenshots, pricing (3 planes), comparison, FAQ, CTA
- Plugin VivesPOS.Site with ContactForm
- Dockerfile: PHP 8.2 Apache, port 80, healthcheck
- Added winter/wn-pages, blog, sitemap, seo plugins
- Active theme set to vivespos

modules/system/controllers/MailTemplates.php

@@ -0,0 +1,80 @@
+<?php namespace System\Controllers;
+
+use Mail;
+use Flash;
+use BackendMenu;
+use Backend\Classes\Controller;
+use System\Models\MailTemplate;
+use System\Classes\SettingsManager;
+use Exception;
+
+/**
+ * Mail templates controller
+ *
+ * @package winter\wn-system-module
+ * @author Alexey Bobkov, Samuel Georges
+ */
+class MailTemplates extends Controller
+{
+    /**
+     * @var array Extensions implemented by this controller.
+     */
+    public $implement = [
+        \Backend\Behaviors\FormController::class,
+        \Backend\Behaviors\ListController::class,
+    ];
+
+    /**
+     * @var array `ListController` configuration.
+     */
+    public $listConfig = [
+        'templates' => 'config_templates_list.yaml',
+        'layouts' => 'config_layouts_list.yaml',
+        'partials' => 'config_partials_list.yaml'
+    ];
+
+    /**
+     * @var array Permissions required to view this page.
+     */
+    public $requiredPermissions = ['system.manage_mail_templates'];
+
+    /**
+     * Constructor.
+     */
+    public function __construct()
+    {
+        parent::__construct();
+
+        BackendMenu::setContext('Winter.System', 'system', 'settings');
+        SettingsManager::setContext('Winter.System', 'mail_templates');
+    }
+
+    public function index($tab = null)
+    {
+        MailTemplate::syncAll();
+        $this->asExtension('ListController')->index();
+        $this->bodyClass = 'compact-container';
+
+        $this->vars['activeTab'] = $tab ?: 'templates';
+    }
+
+    public function formBeforeSave($model)
+    {
+        $model->is_custom = 1;
+    }
+
+    public function onTest($recordId)
+    {
+        try {
+            $model = $this->formFindModelObject($recordId);
+            $user = $this->user;
+
+            Mail::sendTo([$user->email => $user->full_name], $model->code);
+
+            Flash::success(trans('system::lang.mail_templates.test_success'));
+        }
+        catch (Exception $ex) {
+            Flash::error($ex->getMessage());
+        }
+    }
+}