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

themes/demo/assets/less/theme.less

@@ -0,0 +1,46 @@
+//
+// Boot theme
+//
+
+@import "theme/boot";
+
+//
+// Fonts
+//
+
+@import "theme/fonts";
+
+//
+// Controls
+//
+// These are interactive controls used in the site.
+//
+
+@import "controls/example";
+
+//
+// Elements
+//
+// These are reusable elements used in the site.
+//
+
+@import "elements/callouts";
+@import "elements/utilities";
+@import "elements/navbar";
+
+//
+// Layouts
+//
+// Include these here, or directly on the layouts
+//
+
+@import "layouts/default";
+
+//
+// Pages
+//
+// Include these here, or directly on the pages
+//
+
+@import "pages/ajax";
+@import "pages/plugins";