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/wire_connectivity.py

@@ -9,6 +9,7 @@ coordinate matching, mirroring KiCad's own connectivity algorithm.
 import logging
 from pathlib import Path
 from typing import Dict, List, Optional, Set, Tuple
+
 from commands.pin_locator import PinLocator
 
 logger = logging.getLogger("kicad_interface")