fix: update mock target for get_python_files in test after refactor to file_scanner

tests/test_agents.py

@@ -82,7 +82,7 @@ async def test_code_review_agent_no_source_files():
         name="repo",
         local_path="/tmp/fake",
     )
-    with patch("app.agents.code_review_agent.get_python_files", return_value=[]):
+    with patch("app.tools.file_scanner.get_python_files", return_value=[]):
         result = await code_review_agent.run("/tmp/fake", metadata)
     assert result.overall_score == 0.0
     assert "No source files" in result.summary