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/assets/css/relation.css

@@ -0,0 +1,39 @@
+.relation-behavior {
+  margin-bottom: 20px;
+}
+.relation-behavior .control-list {
+  border: 1px solid #eeeeee;
+}
+.relation-behavior .control-list thead > tr > th {
+  border-top: none !important;
+  border-color: #eeeeee;
+}
+.relation-behavior .control-toolbar {
+  padding: 0 20px 20px 20px;
+}
+.relation-behavior .control-toolbar .toolbar-item .form-control.search {
+  padding-top: 5px;
+  padding-bottom: 5px;
+}
+.relation-behavior .control-toolbar .loading-indicator-container.size-input-text {
+  min-height: 0;
+}
+.relation-behavior .control-toolbar .loading-indicator-container.size-input-text .loading-indicator > span {
+  top: 4px;
+}
+.relation-behavior .list-header {
+  padding: 0;
+}
+.relation-behavior .control-list:last-child > table {
+  margin-bottom: 0;
+}
+.relation-flush .control-list {
+  border-top: none;
+}
+.relation-inset {
+  margin-left: -20px;
+  margin-right: -20px;
+}
+.form-group > .relation-behavior .control-toolbar {
+  padding: 0 0 10px 0;
+}