feat: self-host all JS/CSS (GDPR) + clicksports map tiles

- Leaflet, TopJSON, Chart.js, Mermaid served from /js/
- Leaflet CSS from /css/leaflet.min.css
- World atlas GeoJSON from /data/countries-110m.json
- Zero external CDN requests (GDPR compliant)
- Map tiles from maps.clicksports.de (fixed missing Noto Sans font)
- Attribution: clicksports maps + OpenMapTiles + OpenStreetMap
- window.load for script initialization (load order fix)

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

layouts/shortcodes/legislation-timeline.html

@@ -76,7 +76,7 @@ timeline
   </div>
 </div>
 
-<script src="https://cdn.jsdelivr.net/npm/mermaid@11/dist/mermaid.min.js"></script>
+<script src="{{ "js/mermaid.min.js" | relURL }}"></script>
 <script>
 mermaid.initialize({ startOnLoad: true, theme: 'neutral', timeline: { useMaxWidth: true } });
 </script>