Sync notes through GPX, Journal, and Planner roundtrip

Full notes lifecycle:
- GPX: description field in GpxData, <metadata><desc> in generate/parse
- Export: Plan GPX and Save to Journal include notes as description
- Journal: updateRoute extracts description from GPX, stores on route
- Reimport: Edit in Planner passes notes via URL params → Yjs Y.Text
- Drop import: GPX with <desc> restores notes in session

Spec updated: session-notes gains GPX export, Journal sync, and
reimport requirements.

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

apps/planner/app/components/ExportButton.tsx

@@ -69,7 +69,8 @@ export function ExportButton({ yjs }: { yjs: YjsState }) {
     const tracks = getTracks(yjs);
     const waypoints = getWaypoints(yjs);
     const noGoAreas = getNoGoAreas(yjs);
-    const gpx = generateGpx({ name: "trails.cool route", waypoints, tracks, noGoAreas });
+    const notes = yjs.notes.toString() || undefined;
+    const gpx = generateGpx({ name: "trails.cool route", description: notes, waypoints, tracks, noGoAreas });
     download(gpx, "route-plan.gpx");
     setOpen(false);
   }, [yjs]);

apps/planner/app/components/PlannerMap.tsx

@@ -614,6 +614,12 @@ export function PlannerMap({ yjs, onRouteRequest, highlightPosition, highlighted
           yMap.set("points", area.points);
           yjs.noGoAreas.push([yMap]);
         }
+
+        // Replace notes if GPX has a description
+        if (gpxData.description) {
+          yjs.notes.delete(0, yjs.notes.length);
+          yjs.notes.insert(0, gpxData.description);
+        }
       }, "local");
     } catch {
       onImportError?.(t("importGpxError"));

apps/planner/app/components/SaveToJournalButton.tsx

@@ -48,7 +48,8 @@ export function SaveToJournalButton({ yjs, callbackUrl, callbackToken, returnUrl
         isDayBreak: yMap.get("overnight") === true ? true : undefined,
       }));
 
-      const gpx = generateGpx({ name: "trails.cool route", waypoints, tracks, noGoAreas });
+      const notes = yjs.notes.toString() || undefined;
+      const gpx = generateGpx({ name: "trails.cool route", description: notes, waypoints, tracks, noGoAreas });
 
       // POST to Journal callback
       const response = await fetch(callbackUrl, {

apps/planner/app/components/SessionView.tsx

@@ -152,12 +152,13 @@ interface SessionViewProps {
   returnUrl?: string;
   initialWaypoints?: Array<{ lat: number; lon: number; name?: string; isDayBreak?: boolean }>;
   initialNoGoAreas?: Array<{ points: Array<{ lat: number; lon: number }> }>;
+  initialNotes?: string;
 }
 
-export function SessionView({ sessionId, callbackUrl, callbackToken, returnUrl, initialWaypoints, initialNoGoAreas }: SessionViewProps) {
+export function SessionView({ sessionId, callbackUrl, callbackToken, returnUrl, initialWaypoints, initialNoGoAreas, initialNotes }: SessionViewProps) {
   const { t } = useTranslation("planner");
   useEffect(() => { Sentry.setTag("session_id", sessionId); }, [sessionId]);
-  const yjs = useYjs(sessionId, initialWaypoints, initialNoGoAreas);
+  const yjs = useYjs(sessionId, initialWaypoints, initialNoGoAreas, initialNotes);
   const { computing, routeError, routeStats, requestRoute } = useRouting(yjs);
   const { canUndo, canRedo, undo, redo } = useUndo(yjs?.undoManager ?? null);
   useUndoShortcuts(yjs?.undoManager ?? null);