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/dropdown.variables.less

@@ -0,0 +1,22 @@
+@dropdown-bg:                    #fff;
+@dropdown-border:                @overlay-background;
+@dropdown-fallback-border:       #ccc;
+@dropdown-divider-bg:            #e5e5e5;
+
+@dropdown-link-color:            #39454a;
+@dropdown-link-hover-color:      darken(@gray-dark, 5%);
+@dropdown-link-hover-bg:         #f5f5f5;
+
+@dropdown-link-active-color:     @component-active-color;
+@dropdown-link-active-bg:        @component-active-bg;
+
+@dropdown-link-disabled-color:   @gray-light;
+
+@dropdown-header-color:          @gray-light;
+
+@color-dropdown-title-border:    #c9c9c9;
+@color-dropdown-title-text:      @dropdown-link-color;
+@color-dropdown-hover-bg:        @highlight-hover-bg;
+@color-dropdown-hover-text:      @highlight-hover-text;
+@color-dropdown-active-bg:       @highlight-active-bg;
+@color-dropdown-active-text:     @highlight-active-text;