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/media/css/system/searchtools/searchtools.css

@@ -4,15 +4,6 @@
  This file is part of a Moko Consulting project.
 
  SPDX-License-Identifier: GPL-3.0-or-later
-
-
-
- # FILE INFORMATION
- DEFGROUP: Joomla.Template.Site
- INGROUP: MokoCassiopeia
- PATH: ./media/templates/site/mokocassiopeia/css/system/searchtools/searchtools.css
- VERSION: 03.09.02
- BRIEF: Stylesheet for Joomla search tools integration in MokoCassiopeia template
  */
 
 .js-stools-container-bar {