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/behaviors/relationcontroller/partials/_button_unlink.php

@@ -0,0 +1,9 @@
+<a
+    href="javascript:;"
+    class="btn btn-sm btn-secondary wn-icon-unlink"
+    data-request="onRelationButtonUnlink"
+    data-request-success="$.wn.relationBehavior.changed('<?= e($relationField) ?>', 'removed')"
+    data-request-confirm="<?= e(trans('backend::lang.relation.unlink_confirm')) ?>"
+    data-stripe-load-indicator>
+    <?= e(trans($text)) ?>
+</a>