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.

src/pygui/ISC/Tabs/components/ReadoutPanel.qml

@@ -12,6 +12,7 @@ ColumnLayout {
     spacing: 6
     property var s: streamController.stats
     property alias showLabels: labelsToggle.checked
+    property alias showExtremes: extremesToggle.checked
     property alias heatmapBlend: heatmapSlider.value
     property alias showThickness: thicknessToggle.checked
 
@@ -353,6 +354,13 @@ ColumnLayout {
                 font.pixelSize: Theme.fontSm
             }
 
+            PanelCheckBox {
+                id: extremesToggle
+                text: "Highlight Min/Max"
+                checked: true
+                font.pixelSize: Theme.fontSm
+            }
+
             PanelCheckBox {
                 id: clusterAverageToggle
                 text: "Average Clusters"