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/form.mixins.less

@@ -0,0 +1,79 @@
+
+// Form validation states
+//
+// Used in forms.less to generate the form validation CSS for warnings, errors,
+// and successes.
+
+.form-control-validation(@text-color: #555; @border-color: #ccc; @background-color: #f5f5f5) {
+    // Color the label and help text
+    .help-block,
+    .control-label,
+    .radio,
+    .checkbox,
+    .radio-inline,
+    .checkbox-inline {
+        color: @text-color;
+    }
+    // Set the border and box shadow on specific inputs to match
+    .form-control {
+        border-color: @border-color;
+        &:focus {
+            border-color: darken(@border-color, 10%);
+        }
+    }
+    // Set validation states also for addons
+    .input-group-addon {
+        color: @text-color;
+        border-color: @border-color;
+        background-color: @background-color;
+    }
+    // Optional feedback icon
+    .form-control-feedback {
+        color: @text-color;
+    }
+}
+
+// Form control focus state
+//
+// Generate a customized focus state and for any input with the specified color,
+// which defaults to the `@input-focus-border` variable.
+//
+// We highly encourage you to not customize the default value, but instead use
+// this to tweak colors on an as-needed basis. This aesthetic change is based on
+// WebKit's default styles, but applicable to a wider range of browsers. Its
+// usability and accessibility should be taken into account with any change.
+//
+// Example usage: change the default blue border and shadow to white for better
+// contrast against a dark gray background.
+
+.form-control-focus(@color: @input-border-focus) {
+    @color-rgba: rgba(red(@color), green(@color), blue(@color), .6);
+    &:focus {
+        border-color: @color;
+        outline: 0;
+    }
+}
+
+// Form control sizing
+//
+// Relative text size, padding, and border-radii changes for form controls. For
+// horizontal sizing, wrap controls in the predefined grid classes. `<select>`
+// element gets special love because it's special, and that's a fact!
+
+.input-size(@input-height; @padding-vertical; @padding-horizontal; @font-size; @line-height; @border-radius) {
+    height: @input-height;
+    padding: @padding-vertical @padding-horizontal;
+    font-size: @font-size;
+    line-height: @line-height;
+    .border-radius(@border-radius);
+
+    select& {
+        height: @input-height;
+        line-height: @input-height;
+    }
+
+    textarea&,
+    select[multiple]& {
+        height: auto;
+    }
+}