Fix VuMarkTarget import: use mock_vws.target not mock_vws.database

mypy flags VuMarkTarget as not explicitly exported from mock_vws.database;
import it from mock_vws.target instead.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: adamtheturtle

tests/conftest.py

@@ -7,7 +7,8 @@
 
 import pytest
 from mock_vws import MockVWS
-from mock_vws.database import CloudDatabase, VuMarkDatabase, VuMarkTarget
+from mock_vws.database import CloudDatabase, VuMarkDatabase
+from mock_vws.target import VuMarkTarget
 
 from vws import VWS, CloudRecoService, VuMarkService