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/assets/less/winter.less

@@ -0,0 +1,56 @@
+// Vendor
+@import "../vendor/sweet-alert/sweet-alert.less";
+@import "../vendor/jcrop/css/jquery.Jcrop.min.css";
+@import "../../../system/assets/vendor/prettify/prettify.css";
+@import "../../../system/assets/vendor/prettify/theme-desert.css";
+
+//
+// Winter Controls
+//
+
+@import "core/boot.less";
+@import "controls/alert.less";
+@import "controls/global-notice.less";
+@import "controls/simplelist.less";
+@import "controls/scrollbar.less";
+@import "controls/filelist.less";
+@import "controls/common.less";
+@import "controls/reportwidgets.less";
+@import "controls/treelist.less";
+@import "controls/treeview.less";
+@import "controls/sidenav-tree.less";
+@import "controls/panels.less";
+@import "controls/selector-group.less";
+@import "controls/tree-path.less";
+@import "controls/namevaluelist.less";
+@import "controls/scrollpad.less";
+@import "controls/svg-icons.less";
+@import "controls/record-navigation.less";
+
+//
+// Winter Storm UI
+//
+
+@import "../../../system/assets/ui/less/global.less";
+
+//
+// Combines layout and vendor styles
+//
+
+// Core (shared elements)
+@import "core/animations.less";
+
+// Boot variables and mixins
+@import "core/variables.less";
+@import "core/mixins.less";
+
+// Layout
+@import "layout/layout.less";
+@import "layout/flexlayout.less";
+@import "layout/mainmenu.less";
+@import "layout/sidenav.less";
+@import "layout/sidepanel.less";
+@import "layout/footer.less";
+@import "layout/outerlayout.less";
+@import "layout/fancylayout.less";
+@import "layout/flyout.less";