refactor(new_editor): continue architecture closeout

new_editor/include/XCEditor/Docking/UIEditorDockHost.h

@@ -21,11 +21,9 @@ enum class UIEditorDockHostHitTargetKind : std::uint8_t {
     SplitterHandle,
     TabStripBackground,
     Tab,
-    TabCloseButton,
     PanelHeader,
     PanelBody,
-    PanelFooter,
-    PanelCloseButton
+    PanelFooter
 };
 
 struct UIEditorDockHostHitTarget {
@@ -95,7 +93,6 @@ struct UIEditorDockHostPalette {
 struct UIEditorDockHostTabItemLayout {
     std::string panelId = {};
     std::string title = {};
-    bool closable = true;
     bool active = false;
 };