refactor(types): auto -> None sweep across entire codebase

Applied 236 return type annotations to functions with no return values
across 100+ files (core modules, tests, scripts, simulations).
Added Phase 4 to python_style_refactor track for remaining 597 items
(untyped params, vars, and functions with return values).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/test_gemini_cli_adapter_parity.py

@@ -15,7 +15,7 @@ from gemini_cli_adapter import GeminiCliAdapter
 
 class TestGeminiCliAdapterParity(unittest.TestCase):
 
- def setUp(self):
+ def setUp(self) -> None:
   """Set up a fresh adapter instance and reset session state for each test."""
   # Patch session_logger to prevent file operations during tests
   self.session_logger_patcher = patch('gemini_cli_adapter.session_logger')
@@ -25,7 +25,7 @@ class TestGeminiCliAdapterParity(unittest.TestCase):
   self.adapter.last_usage = None
   self.adapter.last_latency = 0.0
 
- def tearDown(self):
+ def tearDown(self) -> None:
   self.session_logger_patcher.stop()
 
  @patch('subprocess.Popen')