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/system/assets/ui/less/select.variables.less

@@ -0,0 +1,21 @@
+//
+// Variables
+// --------------------------------------------------
+
+@color-select-icon:                   #666666;
+@color-select-border:                 #b2b9be;
+@color-select-border-focus:           #808c8d;
+@color-select-bg:                     #f6f6f6;
+@color-select-hover-bg:               #f5f5f5;
+@color-select-hover:                  darken(@gray-dark, 5%);
+@color-select-active:                 #fff;
+@color-select-active-bg:              @brand-secondary;
+@color-select-header:                 @gray-light;
+@color-select-link-disabled:          @gray-light;
+@color-select-choice-bg:              #fff;
+@color-select-choice-border:          #ccc;
+@color-select-text:                   #515c5d;
+
+@select-box-shadow: 0 3px 6px rgba(0,0,0,.075);
+@select-box-shadow-above: 0 -3px 6px rgba(0,0,0,.075);
+@select-cursor-disabled: not-allowed;