feat(map): add min/max highlighting toggle and live safeguards

- Add "Highlight Min/Max" option to ReadoutPanel showing peak rings.
- Reset to review mode and blank wafer map when switching away from map tab.
- Disable hover highlights and sensor dialog triggers during live stream.
- Lower trendPane height and add top margin headroom for tick labels.
- Add test coverage for blanking states, toggle overrides, and interactions.

tests/test_session_controller.py

@@ -53,6 +53,29 @@ def test_pause_stop_timer(controller):
     controller.stop()
     assert controller.frameIndex == 0
 
+def test_leaving_live_mode_blanks_wafer_map(controller):
+    """Stopping a live session (tab switch → setMode) must not leave stale
+    sensor values on the wafer map — it should read as blank."""
+    frame_signal = MagicMock()
+    controller.frameUpdated.connect(frame_signal)
+
+    controller.setMode("live")
+    controller._on_live_frame(Frame(seq=1, time=0.0, values=[100.0] * 22))
+    assert controller.sensorValues, "sanity: live frame should populate the map"
+
+    controller.setMode("review")
+    assert controller.sensorValues == []
+    assert controller.stats == {}
+    assert frame_signal.called, "QML needs frameUpdated to repaint blank"
+
+
+def test_leaving_live_mode_stops_stream(controller):
+    controller.setMode("live")
+    controller.setMode("review")
+    assert controller._reader is None
+    assert not controller._repaint_timer.isActive()
+
+
 def test_compare_files_integration(controller):
     # Mock the comparisonResult signal
     mock_slot = MagicMock()