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/schemas/tool_schemas.py

@@ -10,7 +10,7 @@ Each tool includes:
 - outputSchema: Optional JSON Schema for return values (structured content)
 """
 
-from typing import Dict, Any
+from typing import Any, Dict
 
 # =============================================================================
 # PROJECT TOOLS