refactor: move shutil import to top of test file and fix whitespace

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

tests/test_file_detail_endpoints.py

@@ -2,6 +2,7 @@
 Tests for file detail view improvements including reprocessing and preview endpoints.
 """
 
+import shutil
 from unittest.mock import MagicMock, patch
 
 import pytest
@@ -268,7 +269,6 @@ class TestSubtaskRetry:
         processed_file = processed_dir / "processed_doc.pdf"
 
         # Copy the sample PDF to processed directory
-        import shutil
         shutil.copy(sample_pdf_path, processed_file)
 
         # Create file record with non-existent local_filename but existing processed_file_path