feat(bec_widgets): mirror the single-point acquisition-method warning in the GUI

Adds a wrapped, styled warning label under "Random shift max" in the
params panel, shown whenever "Single-point scan" is checked and hidden
otherwise -- same reminder tomo_parameters() now prints on the CLI
side: use tomo_acquire_at_angle(angle), not tomo_scan_projection(angle),
when single-point mode is on. Toggled from the existing
_on_single_point_changed() handler, so it updates on both a live edit
and every params-panel refresh (the widget's checkbox state already
drives this handler either way).

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

csaxs_bec/bec_widgets/widgets/tomo_params/tomo_params.py

@@ -386,6 +386,16 @@ class TomoParamsWidget(BECWidget, QWidget):
             max_=10.0,
             decimals=3,
         )
+        self._lbl_single_point_hook_warning = QLabel(
+            "With single-point mode on, acquire a single projection (including inside "
+            "a custom at_each_angle hook) with tomo_acquire_at_angle(angle), not "
+            "tomo_scan_projection(angle) -- the latter always runs a full Fermat scan "
+            "regardless of this setting."
+        )
+        self._lbl_single_point_hook_warning.setWordWrap(True)
+        self._lbl_single_point_hook_warning.setStyleSheet("color: #B8860B;")
+        self._lbl_single_point_hook_warning.setVisible(False)
+        common_form.addRow("", self._lbl_single_point_hook_warning)
         self._pw["at_each_angle_hook"] = QComboBox()
         self._pw["at_each_angle_hook"].setEnabled(False)
         self._pw["at_each_angle_hook"].setToolTip(
@@ -731,6 +741,9 @@ class TomoParamsWidget(BECWidget, QWidget):
         self._pw["stitch_y"].setEnabled(self._edit_mode and not checked)
         # random shift only applies to single-point acquisitions
         self._pw["single_point_random_shift_max"].setEnabled(self._edit_mode and checked)
+        # informational, not an editable field -- shown whenever single-point
+        # is on, in or out of edit mode, mirroring tomo_parameters()'s CLI note
+        self._lbl_single_point_hook_warning.setVisible(checked)
 
     def _on_poll(self) -> None:
         """Periodic refresh: params (guarded against edit mode) + sample name."""