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/backend/formwidgets/fieldset/partials/_fieldset.php

@@ -0,0 +1,9 @@
+<?php $label = object_get($this->config, 'label'); ?>
+
+<fieldset class="fieldset">
+    <?php if ($label): ?>
+        <legend><?= e(trans($label)) ?></legend>
+    <?php endif ?>
+
+    <?= $this->formWidget->render(['section' => 'outside']) ?>
+</fieldset>