Refactor Media Manager sync logic and fix duplication bugs

This major refactor addresses improper image matching and duplication:

- Implemented strict ID-based matching in 'MediaService', removing the greedy filename matching fallback.

- Redesigned synchronization pipeline to treat Google Drive as the Source of Truth, supporting orphan adoption (Shopify -> Drive) and secure uploads.

- Implemented 'gallery_order' using Drive file properties (supporting both v2 and v3 APIs) for stable, drag-and-drop global ordering.

- Added conditional file renaming using timestamps to enforce '_' naming convention without unnecessary renames.

- Fixed runtime errors in 'MediaService' loops and updated 'ShopifyMediaService' GraphQL mutations to match correctly schema.

- Rewrote 'MediaService.test.ts' with robust test cases for strict matching, adoption, sorting, and reordering.

src/services/MockShopifyMediaService.ts

@@ -50,4 +50,8 @@ export class MockShopifyMediaService implements IShopifyMediaService {
           }
       }
   }
+
+  getShopDomain(): string {
+     return 'mock-shop.myshopify.com';
+  }
 }