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_ezdxf_backend.py

@@ -1,6 +1,5 @@
 """Tests for ezdxf backend — no AutoCAD required."""
 
-
 import pytest
 
 pytestmark = pytest.mark.asyncio