Add split export: Export Route vs Export Plan

Split button with default "Export GPX" (track only) and dropdown:
- Export Route: clean track for use in any app
- Export Plan: track + waypoints + no-go areas in GPX extensions
  (trails:planning namespace) for reimporting into the planner

Also:
- Add no-go area serialization to generateGpx (GPX extensions)
- Parse no-go areas from GPX extensions on import
- Initialize no-go areas in Yjs session from imported GPX
- Save to Journal now exports track only (consistent with Export Route)

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

apps/planner/app/components/SaveToJournalButton.tsx

@@ -23,13 +23,7 @@ export function SaveToJournalButton({ yjs, callbackUrl, callbackToken, returnUrl
     setError(null);
 
     try {
-      // Build GPX from current Yjs state
-      const waypoints = yjs.waypoints.toArray().map((yMap: Y.Map<unknown>) => ({
-        lat: yMap.get("lat") as number,
-        lon: yMap.get("lon") as number,
-        name: yMap.get("name") as string | undefined,
-      }));
-
+      // Build GPX from computed track (not editing waypoints).
       let tracks: TrackPoint[][] = [];
       const geojsonStr = yjs.routeData.get("geojson") as string | undefined;
       if (geojsonStr) {
@@ -42,7 +36,7 @@ export function SaveToJournalButton({ yjs, callbackUrl, callbackToken, returnUrl
         } catch { /* invalid geojson */ }
       }
 
-      const gpx = generateGpx({ name: "trails.cool route", waypoints, tracks });
+      const gpx = generateGpx({ name: "trails.cool route", waypoints: [], tracks });
 
       // POST to Journal callback
       const response = await fetch(callbackUrl, {