fix: look up image by world_heritage_site_id instead of image PK

WorldHeritageVm.id is the site ID, not the image record's PK.
Querying by world_heritage_site_id with is_primary/sort_order ordering
returns the primary image for the site, which is what the frontend passes.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: zigzagdev

src/app/Packages/Features/Controller/HeritageImageController.php

@@ -13,7 +13,10 @@ class HeritageImageController extends Controller
 {
     public function proxyImage(Request $request, int $id): Response|JsonResponse
     {
-        $image = Image::find($id);
+        $image = Image::where('world_heritage_site_id', $id)
+            ->orderByDesc('is_primary')
+            ->orderBy('sort_order')
+            ->first();
 
         if ($image === null) {
             return response()->json(['error' => 'Image not found'], 404);