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/connection_schematic.py

@@ -1,15 +1,16 @@
-from skip import Schematic
-import os
 import logging
+import os
 from pathlib import Path
 from typing import Optional
 
+from skip import Schematic
+
 logger = logging.getLogger(__name__)
 
 # Import new wire and pin managers
 try:
-    from commands.wire_manager import WireManager
     from commands.pin_locator import PinLocator
+    from commands.wire_manager import WireManager
 
     WIRE_MANAGER_AVAILABLE = True
 except ImportError: