Add interactive Base 4 track map with Leaflet.js

- Created new track-map page with aerial image and SVG overlay
- Implemented custom rotated square markers with obstacle numbers
- Added admin edit mode for placing and repositioning markers
- Database migration for track_obstacles table
- Modal form for adding new obstacles (replaces browser alerts)
- Drag-to-reposition functionality with auto-save
- Color-coded markers (green/red/black/split) for difficulty levels
- Clickable popups showing obstacle details
- Added track-map to navigation menu and sitemap
- URL rewrite rule for clean /track-map URL

header.php

@@ -258,6 +258,7 @@ if ($headerStyle === 'light') {
                                     <ul class="navigation clearfix">
                                         <li><a href="index">Home</a></li>
                                         <li><a href="about">About</a></li>
+                                        <li><a href="track-map">Track Map</a></li>
                                         <li><a href="trips">Trips</a>
                                             <?php if ($headerStyle === 'dark'): ?>
                                             <ul>