fix: add explicit image names to service aliases for standalone workflows

The standalone repo workflows tag/push specific image names:
- StorageApiPhpClient: keboola/storage-api-tests
- ManageApiPhpClient: keboola/manage-api-tests
- TableBackendUtils: table-utils

Without explicit image: fields, docker compose build wouldn't produce
the expected image names.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: zajca

docker-compose.yml

@@ -11,6 +11,7 @@ services:
   # Alias for standalone repo workflow compatibility
   tests:
     <<: *dev
+    image: keboola/storage-api-tests
 
   dev-xdebug:
     build: