Fix avatar/banner showing broken right after cropping & saving

The cropper's onAvatarSaved/onBannerSaved callback used the url from
image.upload, which points at the temp buffer file. updateAvatar/updateBanner
then move that temp file to the NAS profile dir and delete the local copy, so
the url is dead the moment it's used — the avatar/banner rendered broken until
the next page load (the file itself was saved fine).

- updateAvatar/updateBanner now return the canonical media route URL
  (route('media.avatar'|'media.banner', $relPath)), matching the model's
  avatar_url/banner_url accessors and the project's no-asset('storage/...') rule.
- The image-cropper prefers the update endpoint's returned url over the temp
  image.upload url; falls back to the old behavior when none is returned.

Co-Authored-By: Claude Opus 4.8 <[email protected]>

app/Http/Controllers/UserController.php

@@ -572,7 +572,10 @@ class UserController extends Controller
             $nas->deleteLocalAvatar($user);
         }
 
-        return response()->json(['ok' => true]);
+        // Return the canonical media URL. The url from image.upload points at the
+        // temp file we just moved to NAS and deleted, so the client must use this
+        // instead — otherwise the avatar shows broken until the next page load.
+        return response()->json(['ok' => true, 'url' => route('media.avatar', $relPath)]);
     }
 
     public function updateBanner(Request $request)
@@ -606,6 +609,8 @@ class UserController extends Controller
             $nas->deleteLocalBanner($user);
         }
 
-        return response()->json(['ok' => true]);
+        // Return the canonical media URL (see updateAvatar) so the client updates
+        // the banner in place instead of pointing at the deleted temp file.
+        return response()->json(['ok' => true, 'url' => route('media.banner', $relPath)]);
     }
 }