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/tests/js/helpers/FetchMock.js

@@ -0,0 +1,23 @@
+export default function (dom, statusCode, body, headers, jsonPromise, textPromise) {
+    return function () {
+        return Promise.resolve({
+            ok: statusCode >= 200 && statusCode < 300,
+            status: statusCode,
+            headers: new dom.window.Headers(headers),
+            json: () => {
+                if (jsonPromise) {
+                    return jsonPromise;
+                }
+
+                return Promise.resolve(JSON.parse(body));
+            },
+            text: () => {
+                if (textPromise) {
+                    return textPromise;
+                }
+
+                return Promise.resolve(body);
+            },
+        });
+    }
+};