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/views/mail/partial-header.php

@@ -0,0 +1,17 @@
+name = "Header"
+==
+*** {{ body|trim }} <{{ url }}>
+==
+<tr>
+    <td class="header">
+        {% if url %}
+            <a href="{{ url }}">
+                {{ body }}
+            </a>
+        {% else %}
+            <span>
+                {{ body }}
+            </span>
+        {% endif %}
+    </td>
+</tr>