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/flag.less

@@ -0,0 +1,49 @@
+//
+// Dependencies
+// --------------------------------------------------
+@import "../vendor/flag-icon/less/variables";
+
+//
+// Overriding path variable
+// --------------------------------------------------
+
+@flag-icon-css-path: 'vendor/flag-icon/flags';
+
+//
+// Flag
+// --------------------------------------------------
+
+[class^="flag-"],
+[class*=" flag-"] {
+    background-size: contain;
+    background-position: 50%;
+    background-repeat: no-repeat;
+    position: relative;
+    display: inline-block;
+    width: unit((4 / 3), em);
+    line-height: 1em;
+    &:before {
+        content: "\00a0";
+    }
+    &.oc-flag-squared,
+    &.wn-flag-squared {
+        width: 1em;
+    }
+}
+
+.flag-icon(@country) {
+    .flag-@{country} {
+        background-image: ~"url(@{flag-icon-css-path}@{flag-icon-rect-path}/@{country}.svg)";
+        &.wn-flag-squared,
+        &.oc-flag-squared {
+            background-image: ~"url(@{flag-icon-css-path}@{flag-icon-square-path}/@{country}.svg)";
+        }
+    }
+}
+
+//
+// Generate all flags
+// --------------------------------------------------
+
+@import "../vendor/flag-icon/less/flag-icon-list";
+@import "../vendor/flag-icon/less/flag-icon-more";