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/models/maillayout/columns.yaml

@@ -0,0 +1,13 @@
+# ===================================
+#  Column Definitions
+# ===================================
+
+columns:
+
+    name:
+        label: system::lang.mail_templates.name
+        searchable: true
+
+    code:
+        label: system::lang.mail_templates.code
+        searchable: true

modules/system/models/maillayout/fields.yaml

@@ -0,0 +1,47 @@
+# ===================================
+#  Field Definitions
+# ===================================
+
+fields:
+
+    code:
+        label: system::lang.mail_templates.code
+        comment: system::lang.mail_templates.code_comment
+        span: left
+        context: create
+
+    name@create:
+        label: system::lang.mail_templates.name
+        span: right
+
+    name@update:
+        label: system::lang.mail_templates.name
+
+secondaryTabs:
+    fields:
+
+        content_html:
+            type: codeeditor
+            size: giant
+            tab: system::lang.mail_templates.content_html
+            language: html
+            stretch: true
+
+        content_css:
+            type: codeeditor
+            size: giant
+            tab: system::lang.mail_templates.content_css
+            language: css
+            stretch: true
+
+        content_text:
+            type: textarea
+            size: giant
+            tab: system::lang.mail_templates.content_text
+            stretch: true
+
+        options[disable_auto_inline_css]:
+            label: system::lang.mail_templates.disable_auto_inline_css
+            type: checkbox
+            tab: system::lang.mail_templates.options
+            default: false