Initial commit: Bocken theme for webtrees

Nord-themed dark/light mode family tree theme with:
- Floating glass-morphism header bar
- Auto/light/dark theme toggle with Lucide icons
- Smart SVG logo with theme-aware fill colors
- Active page highlighting with per-menu Nord icon colors
- Language button showing 2-letter abbreviation
- Start page search form
- Mobile responsive icon-only nav
- Custom views inherited from ArgonLight

module.php

@@ -0,0 +1,6 @@
+<?php
+
+namespace Bocken\Themes;
+
+include "BockenTheme.php";
+return new BockenTheme();