feat: group beam mark/center/size under one Beam Config banner

The three small beam panels shared a column with three collapsible
banners; BeamConfigPanel puts them under a single collapsible
'Beam Config.' TitleLabel with section_title() sub-headings.
beam_mark/beam_center/beam_size stay as aliases on BeamlineControls so
main_window signal wiring is untouched.

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

src/aare/gui/panels/beam_center_panel.py

@@ -3,7 +3,7 @@ from PySide6.QtCore import Signal, Slot
 from PySide6.QtWidgets import QGridLayout, QLabel, QWidget
 
 from aare.gui.widgets.number_line_edit import NumberLineEdit
-from aare.gui.widgets.title_label import TitleLabel
+from aare.gui.widgets.title_label import section_title
 
 
 class BeamCenterWidget(QWidget):
@@ -14,9 +14,7 @@ class BeamCenterWidget(QWidget):
 
         grid_layout = QGridLayout(self)
 
-        grid_layout.addWidget(
-            TitleLabel("Beam center (detector)", self, collapsible=True), 0, 0, 1, 5
-        )
+        grid_layout.addWidget(section_title("Beam center (detector)", self), 0, 0, 1, 5)
 
         self.x = NumberLineEdit(-4000, 4000, 0, parent=self)
         self.x.newValue.connect(self.beam_center_edited)

src/aare/gui/panels/beam_mark_panel.py

@@ -2,7 +2,7 @@ from aarecommon.models.models import DAQStatusModel
 from PySide6.QtCore import Signal, Slot
 from PySide6.QtWidgets import QGridLayout, QLabel, QPushButton, QWidget
 
-from aare.gui.widgets.title_label import TitleLabel
+from aare.gui.widgets.title_label import section_title
 
 
 class BeamMarkWidget(QWidget):
@@ -13,7 +13,7 @@ class BeamMarkWidget(QWidget):
 
         grid_layout = QGridLayout(self)
 
-        grid_layout.addWidget(TitleLabel("Beam mark (image)", self, collapsible=True), 0, 0, 1, 5)
+        grid_layout.addWidget(section_title("Beam mark (image)", self), 0, 0, 1, 5)
 
         self.x = QLabel("0")
         self.y = QLabel("0")

src/aare/gui/panels/beam_size_panel.py

@@ -3,7 +3,7 @@ from PySide6.QtCore import Signal, Slot
 from PySide6.QtWidgets import QGridLayout, QLabel, QWidget
 
 from aare.gui.widgets.number_line_edit import NumberLineEdit
-from aare.gui.widgets.title_label import TitleLabel
+from aare.gui.widgets.title_label import section_title
 
 
 class BeamSizeWidget(QWidget):
@@ -14,7 +14,7 @@ class BeamSizeWidget(QWidget):
 
         grid_layout = QGridLayout(self)
 
-        grid_layout.addWidget(TitleLabel("Beam size", self, collapsible=True), 0, 0, 1, 5)
+        grid_layout.addWidget(section_title("Beam size", self), 0, 0, 1, 5)
 
         self.x = NumberLineEdit(1, 400.0, 10, parent=self)
         self.x.newValue.connect(self.beam_size_edited)

src/aare/gui/panels/beamline_controls.py

@@ -1,4 +1,4 @@
-from PySide6.QtWidgets import QFrame, QVBoxLayout
+from PySide6.QtWidgets import QFrame, QVBoxLayout, QWidget
 
 from aare.gui.panels.abr_tweak_panel import AbrTweakWidget
 from aare.gui.panels.beam_center_panel import BeamCenterWidget
@@ -10,7 +10,30 @@ from aare.gui.panels.omega_panel import OmegaPanel
 from aare.gui.panels.samcam_panel import SamcamPanel
 from aare.gui.panels.smargon_panel import SmargonPanel
 from aare.gui.panels.zoom_panel import ZoomPanel
-from aare.gui.widgets.title_label import tighten_column
+from aare.gui.widgets.title_label import TitleLabel, tighten_column
+
+
+class BeamConfigPanel(QWidget):
+    """Beam mark / center / size grouped under one collapsible banner; the
+    sub-widgets keep their own signals and small section titles."""
+
+    def __init__(self, parent=None):
+        super().__init__(parent)
+        # Default layout margins so the banner aligns with the sibling
+        # panels' banners in the column.
+        layout = QVBoxLayout(self)
+        layout.setSpacing(0)
+        layout.addWidget(TitleLabel("Beam Config.", self, collapsible=True))
+        self.beam_mark = BeamMarkWidget(self)
+        self.beam_center = BeamCenterWidget(self)
+        self.beam_size = BeamSizeWidget(self)
+        for sub in (self.beam_mark, self.beam_center, self.beam_size):
+            sub_layout = sub.layout()
+            assert sub_layout is not None  # each sub-widget builds its grid in __init__
+            # The outer layout already indents; zero the sub-grids' side
+            # margins so section content isn't double-inset.
+            sub_layout.setContentsMargins(0, 4, 0, 4)
+            layout.addWidget(sub)
 
 
 class BeamlineControls(QFrame):
@@ -42,15 +65,15 @@ class BeamlineControls(QFrame):
         if staff:
             self.monochromator_panel = MonochromatorPanel(self)
             self.abr_tweak = AbrTweakWidget(self)
-            self.beam_mark = BeamMarkWidget(self)
-            self.beam_center = BeamCenterWidget(self)
-            self.beam_size = BeamSizeWidget(self)
+            self.beam_config = BeamConfigPanel(self)
+            # Aliases: main_window wires signals via beamline.beam_mark etc.
+            self.beam_mark = self.beam_config.beam_mark
+            self.beam_center = self.beam_config.beam_center
+            self.beam_size = self.beam_config.beam_size
 
             self.v_layout.addWidget(self.monochromator_panel)
             self.v_layout.addWidget(self.abr_tweak)
-            self.v_layout.addWidget(self.beam_mark)
-            self.v_layout.addWidget(self.beam_center)
-            self.v_layout.addWidget(self.beam_size)
+            self.v_layout.addWidget(self.beam_config)
 
         self.v_layout.addStretch()
         tighten_column(self.v_layout)