🔧 Utilise l'id plutôt que le nom

Comme ça, s'il change, on est safe

app/Deal.php

@@ -91,6 +91,17 @@ class Deal
         return $this->data['price'];
     }
 
+    /**
+     * @return int
+     */
+    public function getIdCategory(): int
+    {
+        return (int) $this->data['category'];
+    }
+
+    /**
+     * @return string
+     */
     public function getCategory(): string
     {
         return Categories::$categories[$this->data['category']];

resources/views/update.blade.php

@@ -25,7 +25,7 @@
                         <select id="category" name="category">
                             <option value="">−</option>
                             @foreach(\Shikiryu\LBCReposter\Categories::$categories as $id => $category)
-                            <<option value="{{ $id }}" @if( $deal->getCategory() === $category ) selected="selected" @endif>{{ $category }}</option>
+                            <<option value="{{ $id }}" @if( $deal->getIdCategory() === $id ) selected="selected" @endif>{{ $category }}</option>
                             @endforeach
                         </select><br>
                         <input type="submit" value="Modifier" />