style: apply ruff format across the repository

ruff format was never run repo-wide; CI now enforces 'ruff format --check', so normalize every module once. No behavior changes.

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/test_drawing.py

@@ -33,6 +33,7 @@ async def test_drawing_export_dxf(backend, tmp_path):
     result = await backend.drawing_export_dxf(export_path)
     assert result.get("ok") is True
     import os
+
     assert os.path.exists(export_path)