feat: fold expanded help cheatsheet when mouse leaves the box

Click is no longer the only way back to the "?" badge: moving the
pointer off the expanded box, or out of the widget entirely, folds it.
Checked before the interaction gate so it works in viewing mode too.

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

src/aare/gui/widgets/camera_image.py

@@ -585,6 +585,11 @@ class SampleCameraImageLabel(QGraphicsView):
         if self._hover_pos is not None:
             self._hover_pos = None
             self.update()
+        if self._help_expanded:
+            # Pointer left the widget with the cheatsheet open — fold it,
+            # same as wandering off the box below.
+            self._help_expanded = False
+            self.update()
         super().leaveEvent(event)
 
     def mouseMoveEvent(self, event):
@@ -593,6 +598,19 @@ class SampleCameraImageLabel(QGraphicsView):
         self._hover_pos = self.mapToScene(event.pos())
         self.update()
 
+        # Expanded help folds when the pointer wanders off the box — click
+        # is not the only way back to the "?" badge. Before the gate: the
+        # badge is a pure UI affordance, live even in viewing mode.
+        if (
+            self._help_expanded
+            and self._help_hit_rect is not None
+            and not self._help_hit_rect.contains(
+                QPointF(self.viewport().mapFrom(self, event.pos()))
+            )
+        ):
+            self._help_expanded = False
+            self.update()
+
         # Badge hover feedback must run BEFORE the interaction gate: the
         # badge is visible precisely when interaction is disabled.
         hovered = self._session_badge_rect is not None and self._session_badge_rect.contains(