style: sort Python imports with isort

Add isort configuration (profile=black, line_length=100) to pyproject.toml,
add isort pre-commit hook, and auto-sort imports across all Python source files.

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

python/commands/svg_import.py

@@ -15,13 +15,13 @@ Supported SVG elements:
 SVG coordinate system: Y increases downward (same as KiCAD mm), so no Y-flip needed.
 """
 
-import re
-import math
-import uuid
-import os
 import logging
-from typing import List, Tuple, Dict, Any, Optional
+import math
+import os
+import re
+import uuid
 import xml.etree.ElementTree as ET
+from typing import Any, Dict, List, Optional, Tuple
 
 logger = logging.getLogger("kicad_interface")