chore: apply linting fixes and expand ruff coverage to test suite

tests/test_session_controller.py

@@ -1,7 +1,10 @@
+from unittest.mock import MagicMock
+
 import pytest
-from unittest.mock import MagicMock, patch
+
 from pygui.backend.controllers.session_controller import SessionController
 
+
 @pytest.fixture
 def controller():
     return SessionController()
@@ -9,7 +12,7 @@ def controller():
 def test_initial_default(controller):
     assert controller.mode == "review"
     assert controller.state == "idle"
-    assert controller.recording == False
+    assert not controller.recording
 
 def test_playback_flow(controller):
     controller.loadFile("tests/fixtures/sample_stream.csv")
@@ -223,10 +226,10 @@ Item {
 def test_recording_toggle(controller, tmp_path):
     csv_path = str(tmp_path / "rec" / "live_test.csv")
     controller.startRecording(csv_path, "SN123")
-    assert controller.recording == True
+    assert controller.recording
 
     controller.stopRecording()
-    assert controller.recording == False
+    assert not controller.recording
 
     # Header written with wafer serial
     content = open(csv_path).read()
@@ -252,4 +255,4 @@ def test_split_data_integration(controller):
     assert mock_slot.call_count == 1
     args = mock_slot.call_args[0][0]
     assert args["success"] is True
-    assert "segments" in args
+    assert "segments" in args