feat: add carpet

lib/core/network/card_images.dart

@@ -57,6 +57,22 @@ class CardImages {
     }
   }
 
+  /// تصویرِ فرش (برای سطحِ میز) از backend: `/carpets/<id>.jpg`. کش‌شده.
+  static Future<Sprite?> carpet(String id) {
+    return _cache.putIfAbsent('carpet/$id', () async {
+      try {
+        final res = await _dio
+            .get<List<int>>('${AppConfig.baseUrl}/carpets/$id.jpg');
+        final data = res.data;
+        if (data == null || data.isEmpty) return null;
+        return Sprite(await _decode(Uint8List.fromList(data)));
+      } catch (e) {
+        debugPrint('CardImages: carpet/$id failed: $e');
+        return null;
+      }
+    });
+  }
+
   static Future<ui.Image> _decode(Uint8List bytes) async {
     final codec = await ui.instantiateImageCodec(bytes);
     final frame = await codec.getNextFrame();