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/tests/fixtures/plugins/winter/replacenotinstalled/Plugin.php

@@ -0,0 +1,20 @@
+<?php
+
+namespace Winter\ReplaceNotInstalled;
+
+use System\Classes\PluginBase;
+
+class Plugin extends PluginBase
+{
+    public function pluginDetails()
+    {
+        return [
+            'name' => 'Winter Sample Plugin',
+            'description' => 'Sample plugin used by unit tests.',
+            'author' => 'Alexey Bobkov, Samuel Georges',
+            'replaces' => [
+                'Winter.NotInstalled' => '>=1.0.3'
+            ]
+        ];
+    }
+}