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/models/MailBrandSettingTest.php

@@ -0,0 +1,57 @@
+<?php
+
+namespace System\Tests\Models;
+
+use System\Models\MailBrandSetting;
+use System\Tests\Bootstrap\PluginTestCase;
+
+class MailBrandSettingTest extends PluginTestCase
+{
+    public function setUp(): void
+    {
+        parent::setUp();
+
+        \System\Behaviors\SettingsModel::clearInternalCache();
+    }
+
+    public function tearDown(): void
+    {
+        MailBrandSetting::instance()->resetDefault();
+        \System\Behaviors\SettingsModel::clearInternalCache();
+
+        parent::tearDown();
+    }
+
+    /**
+     * Regression for GHSA-58fp-mcx6-7qf9. MailBrandSetting takes no raw user CSS
+     * string but flows user input through Less_Parser::ModifyVars(), whose
+     * serializeVars() helper concatenates raw values into LESS source without
+     * escaping. A CSS variable value of `red; @import (inline) "/path/to/secret"`
+     * therefore reaches the parser as a working @import directive. The
+     * SetImportDirs deny-all gate in compileCss() must close this vector
+     * regardless of form-field validation strictness.
+     */
+    public function testCompileCssBlocksModifyVarsImportInjection()
+    {
+        $tmpSecret = tempnam(sys_get_temp_dir(), 'mailbrandsetting-leak-canary-');
+        file_put_contents($tmpSecret, "APP_KEY=do-not-leak-via-modifyvars\n");
+
+        try {
+            // Bypass form-field validation by writing the malicious value directly
+            // onto the model. This simulates a model-layer bypass or a future
+            // weakening of the field validator.
+            $setting = MailBrandSetting::instance();
+            $setting->body_bg = 'red; @import (inline) "' . $tmpSecret . '"';
+            $setting->save();
+
+            \System\Behaviors\SettingsModel::clearInternalCache();
+
+            $css = MailBrandSetting::compileCss();
+
+            $this->assertStringNotContainsString('APP_KEY', $css);
+            $this->assertStringNotContainsString('do-not-leak-via-modifyvars', $css);
+        } finally {
+            @unlink($tmpSecret);
+        }
+    }
+}