Show empty-state CTA on Route detail page when no waypoints

Observed: both non-maintainer users (pistazie, nelli) created a route,
never planned in it, and stopped. The Route detail page rendered as a
dead end — name, a row of buttons, then blank.

Changes:
- Detect "empty" as no geometry AND no distance (the state every new
  route has before any planning happens).
- When empty, hide the top-row button cluster (Edit in Planner / Edit
  / Export GPX) and render a centered dashed-border card in its place.
- Card shows: large headline, short body (owner-specific vs
  viewer-only copy), primary "Open in Planner" button (same action as
  the existing top-row button, just visually prominent), and a
  secondary "or upload a GPX file" link to the edit page.
- Bilingual copy added under routes.empty.*.

No non-empty route loses any UI — those paths stay identical.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/journal/app/routes/routes.$id.tsx

@@ -99,6 +99,11 @@ export default function RouteDetailPage({ loaderData }: Route.ComponentProps) {
   const [editLoading, setEditLoading] = useState(false);
   const [highlightedDay, setHighlightedDay] = useState<number | null>(null);
 
+  // A route is "empty" when it has no geometry and no computed distance —
+  // i.e. nobody has planned any waypoints yet. Surfaced as a dedicated
+  // empty-state below so the page isn't a dead end.
+  const isEmpty = !route.geojson && route.distance == null;
+
   const handleEditInPlanner = useCallback(async () => {
     setEditLoading(true);
     try {
@@ -121,7 +126,7 @@ export default function RouteDetailPage({ loaderData }: Route.ComponentProps) {
             <p className="mt-2 text-gray-600">{route.description}</p>
           )}
         </div>
-        {isOwner && (
+        {isOwner && !isEmpty && (
           <div className="flex flex-wrap gap-2">
             <button
               onClick={handleEditInPlanner}
@@ -222,6 +227,35 @@ export default function RouteDetailPage({ loaderData }: Route.ComponentProps) {
         </div>
       )}
 
+      {isEmpty && (
+        <div className="mt-6 flex flex-col items-center rounded-lg border border-dashed border-gray-300 bg-gray-50 px-6 py-12 text-center">
+          <div className="text-4xl" aria-hidden="true">🗺️</div>
+          <h2 className="mt-4 text-lg font-semibold text-gray-900">
+            {t("routes.empty.heading")}
+          </h2>
+          <p className="mt-2 max-w-md text-sm text-gray-600">
+            {isOwner ? t("routes.empty.bodyOwner") : t("routes.empty.bodyViewer")}
+          </p>
+          {isOwner && (
+            <div className="mt-6 flex flex-wrap items-center justify-center gap-3">
+              <button
+                onClick={handleEditInPlanner}
+                disabled={editLoading}
+                className="rounded-md bg-blue-600 px-4 py-2 text-sm font-medium text-white hover:bg-blue-700 disabled:opacity-50"
+              >
+                {editLoading ? t("routes.opening") : t("routes.empty.openInPlanner")}
+              </button>
+              <a
+                href={`/routes/${route.id}/edit`}
+                className="text-sm text-gray-600 underline hover:text-gray-900"
+              >
+                {t("routes.empty.uploadGpx")}
+              </a>
+            </div>
+          )}
+        </div>
+      )}
+
       {versions.length > 0 && (
         <div className="mt-8">
           <h2 className="text-lg font-semibold text-gray-900">Version History</h2>

packages/i18n/src/locales/de.ts

@@ -179,6 +179,13 @@ export default {
       noRoutesYet: "Noch keine Routen. Erstelle deine erste Route!",
       noMapPreview: "Keine Kartenvorschau",
       saveChanges: "Änderungen speichern",
+      empty: {
+        heading: "Diese Route ist leer",
+        bodyOwner: "Du hast noch keine Wegpunkte geplant. Öffne sie im Planer, um eine Strecke zu skizzieren, oder lade eine GPX-Datei hoch.",
+        bodyViewer: "Diese Route enthält noch keine Wegpunkte.",
+        openInPlanner: "Im Planer öffnen",
+        uploadGpx: "oder eine GPX-Datei hochladen",
+      },
     },
     activities: {
       title: "Aktivitäten",

packages/i18n/src/locales/en.ts

@@ -179,6 +179,13 @@ export default {
       noRoutesYet: "No routes yet. Create your first route!",
       noMapPreview: "No map preview",
       saveChanges: "Save Changes",
+      empty: {
+        heading: "This route is empty",
+        bodyOwner: "You haven't planned any waypoints yet. Open it in the Planner to sketch a path, or upload a GPX file.",
+        bodyViewer: "This route doesn't have any waypoints yet.",
+        openInPlanner: "Open in Planner",
+        uploadGpx: "or upload a GPX file",
+      },
     },
     activities: {
       title: "Activities",