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_headless_service.py

@@ -24,7 +24,7 @@ class TestHeadlessAPI(unittest.TestCase):
    self.api = self.app_instance.create_api()
    self.client = TestClient(self.api)
 
- def test_health_endpoint(self):
+ def test_health_endpoint(self) -> None:
   response = self.client.get("/health")
   self.assertEqual(response.status_code, 200)
   self.assertEqual(response.json(), {"status": "ok"})
@@ -42,7 +42,7 @@ class TestHeadlessAPI(unittest.TestCase):
    response = self.client.get("/status", headers=headers)
    self.assertEqual(response.status_code, 200)
 
- def test_generate_endpoint(self):
+ def test_generate_endpoint(self) -> None:
   payload = {
    "prompt": "Hello AI"
   }
@@ -100,7 +100,7 @@ class TestHeadlessAPI(unittest.TestCase):
    if dummy_log.exists():
     dummy_log.unlink()
 
- def test_get_context_endpoint(self):
+ def test_get_context_endpoint(self) -> None:
   response = self.client.get("/api/v1/context", headers=self.headers)
   self.assertEqual(response.status_code, 200)
   data = response.json()
@@ -152,14 +152,14 @@ class TestHeadlessStartup(unittest.TestCase):
     app.run()
     mock_immapp_run.assert_called_once()
 
-def test_fastapi_installed():
+def test_fastapi_installed() -> None:
  """Verify that fastapi is installed."""
  try:
   importlib.import_module("fastapi")
  except ImportError:
   pytest.fail("fastapi is not installed")
 
-def test_uvicorn_installed():
+def test_uvicorn_installed() -> None:
  """Verify that uvicorn is installed."""
  try:
   importlib.import_module("uvicorn")