fix: respect hideContextPercentage when FooterConfigDialog is closed without changes (#24773)

Co-authored-by: Coco Sheng <cocosheng@google.com>

packages/cli/src/ui/components/FooterConfigDialog.tsx

@@ -13,7 +13,11 @@ import { useUIState } from '../contexts/UIStateContext.js';
 import { useKeypress, type Key } from '../hooks/useKeypress.js';
 import { Command } from '../key/keyMatchers.js';
 import { FooterRow, type FooterRowItem } from './Footer.js';
-import { ALL_ITEMS, resolveFooterState } from '../../config/footerItems.js';
+import {
+  ALL_ITEMS,
+  resolveFooterState,
+  deriveItemsFromLegacySettings,
+} from '../../config/footerItems.js';
 import { SettingScope } from '../../config/settings.js';
 import { BaseSelectionList } from './shared/BaseSelectionList.js';
 import type { SelectionListItem } from '../hooks/useSelectionList.js';
@@ -137,17 +141,16 @@ export const FooterConfigDialog: React.FC<FooterConfigDialogProps> = ({
   const handleSaveAndClose = useCallback(() => {
     const finalItems = orderedIds.filter((id: string) => selectedIds.has(id));
     const currentSetting = settings.merged.ui?.footer?.items;
-    if (JSON.stringify(finalItems) !== JSON.stringify(currentSetting)) {
+    // When items haven't been explicitly set yet (legacy mode), compare against
+    // the legacy-derived items to avoid persisting items and silently overriding
+    // legacy boolean settings like hideContextPercentage.
+    const effectiveCurrent =
+      currentSetting ?? deriveItemsFromLegacySettings(settings.merged);
+    if (JSON.stringify(finalItems) !== JSON.stringify(effectiveCurrent)) {
       setSetting(SettingScope.User, 'ui.footer.items', finalItems);
     }
     onClose?.();
-  }, [
-    orderedIds,
-    selectedIds,
-    setSetting,
-    settings.merged.ui?.footer?.items,
-    onClose,
-  ]);
+  }, [orderedIds, selectedIds, setSetting, settings.merged, onClose]);
 
   const handleResetToDefaults = useCallback(() => {
     setSetting(SettingScope.User, 'ui.footer.items', undefined);