float the selection panel over the game world instead of a side column

src/ui/FieldSelectionPanel.h

@@ -23,8 +23,8 @@ class QVBoxLayout;
 // summary (REQ-UI-SELECTION-CATEGORIES, REQ-UI-FIELD-MULTI-SELECTION, REQ-UI-DEBRIS-PANEL).
 //
 // The panel owns its own selection state and its own widgets, and nothing else. Which of
-// the two selection categories owns the side panel is arbitrated by the parent
-// SelectedBuildingPanel: it feeds this panel through setSelectedEntities() /
+// the two selection categories owns the selection panel is arbitrated by the parent
+// SelectionPanel: it feeds this panel through setSelectedEntities() /
 // setSelectedDebris() / clearSelection() and asks it via hasSelection(). This panel hides
 // itself whenever its selection is empty, so an inactive field category takes no space.
 class FieldSelectionPanel : public QWidget,
@@ -47,7 +47,7 @@ public:
     // Drops the whole field selection — used when the building category takes over.
     void clearSelection();
     // True while the field category has anything selected, i.e. while this panel owns
-    // the side panel's content.
+    // the selection panel's content.
     bool hasSelection() const;
 
 private: