Hero variable system, CSS fallbacks, header cleanup, remove mobile overrides

- Hero card fully variable-driven: --hero-card-bg/color/overlay/border-radius/padding/max-width
- Alternative hero variant: --hero-alt-card-* for secondary theme
- Overlay bg-position and bg-size now customizable via variables
- Mobile breakpoint: photo bg hidden, hero full-bleed on small screens
- Added fallback values to 1365 var() calls in template.css
- .btn --btn-bg changed from transparent to var(--body-bg) in dark/light themes
- .offcanvas-header .btn-close gets background-color from overlay
- Stripped file info headers (@package/DEFGROUP/VERSION) from 48 files, kept copyright/SPDX
- Synced all theme variables across standard and custom templates
- Removed 26 mobile.php layout overrides
- Added *.py to .gitignore, card-border-radius fallback

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/script.php

@@ -1,17 +1,17 @@
 <?php
 /**
- * @package     Joomla.Site
- * @subpackage  Templates.MokoCassiopeia
+ * Copyright (C) 2025 Moko Consulting <hello@mokoconsulting.tech>
  *
- * @copyright   (C) 2026 Moko Consulting <hello@mokoconsulting.tech>
- * @license     GNU General Public License version 2 or later; see LICENSE.txt
+ * This file is part of a Moko Consulting project.
  *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+/**
  * Template install/update/uninstall script.
- *
  * Joomla calls the methods in this class automatically during template
  * install, update, and uninstall via the <scriptfile> element in
  * templateDetails.xml.
- *
  * Joomla 5 and 6 compatible — uses the InstallerScriptInterface when
  * available, falls back to the legacy class-based approach otherwise.
  */