Draw offline hiking trails sharing a path as parallel lanes

Several marked routes running down one path drew as a single line, only
the topmost color visible. maplibre-gl-lanes puts each route in its own
lane; OSM relations already share exact vertices, which is all it needs.
One LaneLayer across every picked country; click hit-testing and the
highlight move to queryLane/setHighlight.

docs/third-party-notices.adoc

@@ -51,6 +51,20 @@ overview's polar pan limit, but MapLibre 6's `Map` no longer exposes
 `.transform` at all — guarded to skip that (cosmetic) adjustment
 instead of throwing when it's absent.
 
+Also vendored under `public/vendor/` — MIT-licensed, attribution
+required (`LICENSE` included alongside):
+
+[cols="1,1,2"]
+|===
+| Library | Version | Source
+
+| maplibre-gl-lanes (offline hiking trails, `public/js/hiking_trails.js`
+— trails sharing a path drawn as parallel lanes); its `dist/*.mjs`
+build, minus the trailing `sourceMappingURL` comment
+| 1.3.0
+| https://github.com/c0nsumer/maplibre-gl-lanes
+|===
+
 Also vendored under `public/vendor/` — MIT-licensed (© 2013 Panayiotis
 Lipiridis), attribution required (this notice satisfies that):