fix: Python 3.8 compatibility for type hints

Changed `tuple[...]` to `Tuple[...]` in type hints for Python 3.8
compatibility. The lowercase generic syntax was introduced in Python 3.9
(PEP 585), but our CI runs on Python 3.8.

Changes:
- Added `Tuple` to typing imports
- Changed return type annotation from `tuple[...]` to `Tuple[...]`

Fixes CI test collection error:
TypeError: 'type' object is not subscriptable

Author: claude

src/harmonizer/main.py

@@ -28,7 +28,7 @@
 import json
 import os
 import sys
-from typing import Dict, List
+from typing import Dict, List, Tuple
 
 # --- COMPONENT IMPORTS ---
 # This script assumes the following two files are in the
@@ -472,7 +472,7 @@ def validate_cli_arguments(args: argparse.Namespace) -> List[str]:
 
 def execute_analysis(
     harmonizer: PythonCodeHarmonizer, file_paths: List[str], output_format: str
-) -> tuple[Dict[str, Dict[str, Dict]], int]:
+) -> Tuple[Dict[str, Dict[str, Dict]], int]:
     """
     Executes the analysis pipeline.
     Pure Power domain: orchestrating the actual work.