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/docs/loader.md

@@ -0,0 +1,91 @@
+# Loading indicators
+
+## Container Loading Indicator
+
+#### Loading Indicator
+A loading indicator used in a container.
+
+    <div class="loading-indicator-container">
+        <div class="loading-indicator">
+            <span></span>
+        </div>
+        <p>This is some content inside the container</p>
+        <p>The loading indicator must be prepended to it</p>
+    </div>
+
+#### Text Loading Indicator
+A loading indicator can have text by adding a `<div>` element inside.
+
+    <div class="loading-indicator-container">
+        <div class="loading-indicator">
+            <span></span>
+            <div>Loading...</div>
+        </div>
+    </div>
+
+#### Loading Indicator Sizes
+
+A loading indicator can have a size by adding `size-X` to the container. These sizes are available: **size-small**.
+
+    <div class="loading-indicator-container">
+        <div class="loading-indicator size-small">
+            <span></span>
+            <div>Loading (size-small)</div>
+        </div>
+    </div>
+
+#### Loading Indicator Alignment
+
+A loading indicator can be aligned to the center by adding `indicator-center` to the container and/or indicator.
+
+    <div class="loading-indicator-container">
+        <div class="loading-indicator indicator-center">
+            <span></span>
+        </div>
+    </div>
+
+You may add some optional text:
+
+    <div class="loading-indicator-container">
+        <div class="loading-indicator indicator-center">
+            <span></span>
+            <div>Loading...</div>
+        </div>
+    </div>
+
+# Example
+
+    <div class="loading-indicator-container">
+        <div class="loading-indicator">
+            <span></span>
+        </div>
+        <p>This is some content inside the container</p>
+        <p>The loading indicator must be prepended to it</p>
+    </div>
+
+    <div class="loading-indicator-container">
+        <div class="loading-indicator">
+            <span></span>
+            <div>Loading...</div>
+        </div>
+    </div>
+
+    <div class="loading-indicator-container">
+        <div class="loading-indicator indicator-inset">
+            <span></span>
+            <div>Loading (inset)</div>
+        </div>
+    </div>
+
+    <div class="loading-indicator-container">
+        <div class="loading-indicator size-small">
+            <span></span>
+            <div>Loading (size-small)</div>
+        </div>
+    </div>
+
+    <div class="loading-indicator-container">
+        <div class="loading-indicator indicator-center">
+            <span></span>
+        </div>
+    </div>