fix: use title-based slugs for new markers

Generate marker slugs from title (e.g., "marqueur-2") instead of
timestamp-based slugs (e.g., "marker-1770362950"). Also fix panelUrl
generation to use Kirby's panel URL method.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

public/site/plugins/map-editor/api/routes.php

@@ -166,9 +166,9 @@ return [
                     ->filterBy('intendedTemplate', 'marker');
                 $nextNum = $existingMarkers->count() + 1;
 
-                // Generate unique slug and title
-                $slug = 'marker-' . time();
+                // Generate title and slug based on title
                 $title = 'Marqueur ' . $nextNum;
+                $slug = Str::slug($title);
 
                 // Create the new marker page
                 $newMarker = $mapPage->createChild([
@@ -307,7 +307,7 @@ return [
                                 'lon' => $lon
                             ],
                             'num' => $marker->num(),
-                            'panelUrl' => '/panel/pages/' . $marker->id(),
+                            'panelUrl' => (string) $marker->panel()->url(),
                             'iconUrl' => $iconUrl,
                             'iconSize' => $iconSize
                         ]