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/backend/controllers/auth/signin.php

@@ -0,0 +1,60 @@
+<h2><?= e(Backend\Models\BrandSetting::get('app_tagline')) ?></h2>
+
+<?= Form::open() ?>
+    <input type="hidden" name="postback" value="1" />
+
+    <div class="form-elements" role="form">
+        <div class="form-group text-field horizontal-form">
+
+            <!-- Login -->
+            <input
+                type="text"
+                name="login"
+                value="<?= e(post('login')) ?>"
+                class="form-control icon user"
+                placeholder="<?= e(trans('backend::lang.account.login_placeholder')) ?>"
+                autocomplete="off"
+                maxlength="255" />
+
+            <!-- Password -->
+            <input
+                type="password"
+                name="password"
+                value=""
+                class="form-control icon lock"
+                placeholder="<?= e(trans('backend::lang.account.password_placeholder')) ?>"
+                autocomplete="off"
+                maxlength="255" />
+
+            <!-- Submit Login -->
+            <button type="submit" class="btn btn-primary login-button">
+                <?= e(trans('backend::lang.account.login')) ?>
+            </button>
+        </div>
+
+        <?php if (is_null(config('cms.backendForceRemember', true))): ?>
+            <!-- Remember checkbox -->
+            <div class="form-group checkbox-field horizontal-form remember">
+                <div class="checkbox custom-checkbox">
+                    <input
+                        type="checkbox"
+                        id="remember"
+                        name="remember" />
+                    <label for="remember">
+                        <?= e(trans('backend::lang.account.remember_me')) ?>
+                    </label>
+                </div>
+            </div>
+        <?php endif; ?>
+
+        <p class="wn-icon-lock pull-right forgot-password">
+            <!-- Forgot your password? -->
+            <a href="<?= Backend::url('backend/auth/restore') ?>" class="text-muted">
+                <?= e(trans('backend::lang.account.forgot_password')) ?>
+            </a>
+        </p>
+
+    </div>
+<?= Form::close() ?>
+
+<?= $this->fireViewEvent('backend.auth.extendSigninView') ?>