feat: add Change Energy row to experiment configuration

Copy of the Beamline Setup energy row (keV display, eV emit), placed
below the ML Loop Centring / Make Raster Grid row and always visible.
Wired to the same daq.change_energy; not staff-gated, server enforces
write permission.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/aare/gui/main_window.py

@@ -925,6 +925,10 @@ class MainWindow(QMainWindow):
         self.beamline.illumination_panel.front_light.connect(self.daq.front_light)
         self.beamline.illumination_panel.back_light.connect(self.daq.back_light)
 
+        # Energy row inside Exp. Config. — not staff-gated like the Beamline
+        # Setup copy; the server enforces write permission anyway.
+        self.data_collection.change_energy.connect(self.daq.change_energy)
+
         if self._decoded_token.staff:
             self.monochromator_panel.mono_pitch_scan.connect(self.daq.mono_pitch_scan)
             self.monochromator_panel.change_energy.connect(self.daq.change_energy)

src/aare/gui/panels/data_collection_settings.py

@@ -3,8 +3,10 @@ from aarecommon.math.sample_geometry import SampleGeometryModel
 from aarecommon.models.models import DAQStatusModel
 from PySide6.QtCore import Signal, Slot
 from PySide6.QtWidgets import (
+    QDoubleSpinBox,
     QFrame,
     QHBoxLayout,
+    QLabel,
     QPushButton,
     QSizePolicy,
     QStackedWidget,
@@ -26,6 +28,8 @@ from aare.gui.widgets.title_label import TitleLabel, tighten_column
 
 class DataCollectionSettings(QFrame):
     cancel = Signal()
+    # Same convention as the Beamline Setup panel: keV in the GUI, eV on emit.
+    change_energy = Signal(float)
 
     set_width = 400
 
@@ -81,6 +85,22 @@ class DataCollectionSettings(QFrame):
         centering_layout.addWidget(self.find_tip)
         centering_layout.addWidget(self.bounding_box)
 
+        # Energy row copied from the Beamline Setup panel so users can change
+        # energy without leaving the experiment configuration.
+        self.energy_spin = QDoubleSpinBox(parent=self)
+        self.energy_spin.setDecimals(3)
+        self.energy_spin.setRange(1.0, 30.0)
+        self.energy_spin.setSingleStep(0.1)
+        self.energy_spin.setValue(12.0)
+        self.change_energy_button = QPushButton("Change Energy", parent=self)
+        self.change_energy_button.clicked.connect(self._emit_change_energy)
+        energy_row = QWidget(self)
+        energy_layout = QHBoxLayout(energy_row)
+        energy_layout.setContentsMargins(0, 0, 0, 0)
+        energy_layout.addWidget(QLabel("Energy (keV)", parent=energy_row))
+        energy_layout.addWidget(self.energy_spin)
+        energy_layout.addWidget(self.change_energy_button)
+
         # Pane frame carries the border QTabWidget::pane used to draw
         # (#expConfigPane rule in styles.py).
         pane = QFrame(self)
@@ -90,6 +110,7 @@ class DataCollectionSettings(QFrame):
         # border, and the Abort button should hug the pane.
         pane_layout.setContentsMargins(6, 6, 6, 0)
         pane_layout.addWidget(centering_row)
+        pane_layout.addWidget(energy_row)
         pane_layout.addWidget(self._stack)
 
         # Own container: TitleLabel collapse hides its siblings, so without it
@@ -147,6 +168,10 @@ class DataCollectionSettings(QFrame):
             page.setSizePolicy(QSizePolicy.Policy.Preferred, vertical)
         self._stack.adjustSize()
 
+    @Slot()
+    def _emit_change_energy(self):
+        self.change_energy.emit(float(self.energy_spin.value()) * 1000.0)
+
     @Slot()
     def switch_to_raster(self):
         self._tab_bar.setCurrentIndex(0)