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/datasheet_manager.py

@@ -9,8 +9,8 @@ URL schema: https://www.lcsc.com/datasheet/{LCSC#}.pdf
 No API key required.
 """
 
-import re
 import logging
+import re
 from pathlib import Path
 from typing import Dict, List, Optional