🐛 fix(update): 修复重启更新时退出确认弹窗被遮挡

- 新增应用退出确认专用层级并动态高于当前设置子弹窗
- 未保存 SQL 与关闭其他实例确认框统一使用前景层级
- 补充更新退出链路与弹层层级回归测试

frontend/src/App.tsx

@@ -210,6 +210,7 @@ import {
   saveApplicationQuitUnsavedSQLTargets,
 } from './utils/sqlEditorApplicationQuit';
 import {
+  APP_APPLICATION_QUIT_MODAL_Z_INDEX,
   APP_FOREGROUND_MODAL_Z_INDEX,
   APP_NESTED_MODAL_Z_INDEX,
   APP_OVERLAY_Z_INDEX_BASE,
@@ -1064,6 +1065,10 @@ function App() {
     APP_NESTED_MODAL_Z_INDEX,
     settingsCenterModalZIndex + 100,
   );
+  const applicationQuitModalZIndex = Math.max(
+    APP_APPLICATION_QUIT_MODAL_Z_INDEX,
+    settingsChildModalZIndex + 100,
+  );
   const toggleAIPanel = useStore(state => state.toggleAIPanel);
   const setAIPanelVisible = useStore(state => state.setAIPanelVisible);
   useEffect(() => {
@@ -2608,6 +2613,7 @@ function App() {
           cancelText: t('app.quit.unsaved_sql.cancel'),
           closable: true,
           maskClosable: false,
+          zIndex: applicationQuitModalZIndex,
           okButtonProps: { danger: true, type: 'primary' },
           footer: (_, { OkBtn, CancelBtn }) => (
               <>
@@ -2643,7 +2649,7 @@ function App() {
       });
       destroyConfirm = confirmRef.destroy;
       applicationQuitConfirmRef.current = confirmRef;
-  }, [forceQuitApplication, resetApplicationQuitRequest, saveQuery, t]);
+  }, [applicationQuitModalZIndex, forceQuitApplication, resetApplicationQuitRequest, saveQuery, t]);
 
   const handleInstallUpdateRequest = useCallback(async () => {
       if (installMode === 'portable' || installMode === 'msi') {
@@ -2654,6 +2660,7 @@ function App() {
               cancelText: t('common.cancel'),
               closable: true,
               maskClosable: false,
+              zIndex: applicationQuitModalZIndex,
               okButtonProps: { danger: true, type: 'primary' },
               onOk: async () => {
                   await handleApplicationQuitRequest(() => handleInstallFromProgress(true));
@@ -2662,7 +2669,7 @@ function App() {
           return;
       }
       await handleApplicationQuitRequest(() => handleInstallFromProgress(false));
-  }, [handleApplicationQuitRequest, handleInstallFromProgress, installMode, t]);
+  }, [applicationQuitModalZIndex, handleApplicationQuitRequest, handleInstallFromProgress, installMode, t]);
 
   useEffect(() => {
       const offBeforeClose = EventsOn('app:before-close-request', () => {

frontend/src/App.update-quit-guard.test.ts

@@ -43,4 +43,21 @@ describe('restart-to-update unsaved SQL guard', () => {
     expect(appSource).toContain("updateInstallAction === 'launch-installer'");
     expect(appSource.match(/\{updateInstallActionLabel\}/g)).toHaveLength(2);
   });
+
+  it('keeps every update quit confirmation above active settings and update dialogs', () => {
+    const unsavedConfirmStart = appSource.indexOf('const confirmRef = Modal.confirm({');
+    const installRequestStart = appSource.indexOf('const handleInstallUpdateRequest = useCallback', unsavedConfirmStart);
+    const installRequestEnd = appSource.indexOf('\n\n  useEffect(() => {', installRequestStart);
+    const unsavedConfirmSource = appSource.slice(unsavedConfirmStart, installRequestStart);
+    const installRequestSource = appSource.slice(installRequestStart, installRequestEnd);
+
+    expect(unsavedConfirmStart).toBeGreaterThan(-1);
+    expect(installRequestStart).toBeGreaterThan(unsavedConfirmStart);
+    expect(installRequestEnd).toBeGreaterThan(installRequestStart);
+    expect(appSource).toContain('APP_APPLICATION_QUIT_MODAL_Z_INDEX,');
+    expect(appSource).toContain('const applicationQuitModalZIndex = Math.max(');
+    expect(appSource).toContain('settingsChildModalZIndex + 100,');
+    expect(unsavedConfirmSource).toContain('zIndex: applicationQuitModalZIndex');
+    expect(installRequestSource).toContain('zIndex: applicationQuitModalZIndex');
+  });
 });

frontend/src/utils/overlayZIndex.test.ts

@@ -5,6 +5,7 @@ import * as ts from 'typescript';
 import { afterEach, describe, expect, it, vi } from 'vitest';
 
 import {
+  APP_APPLICATION_QUIT_MODAL_Z_INDEX,
   APP_COMMAND_PALETTE_Z_INDEX,
   APP_DETACHED_WINDOW_Z_INDEX_BASE,
   APP_FOREGROUND_MODAL_Z_INDEX,
@@ -110,6 +111,7 @@ describe('application overlay z-index policy', () => {
     expect(APP_FOREGROUND_MODAL_Z_INDEX).toBeGreaterThan(APP_POPUP_Z_INDEX);
     expect(APP_NESTED_MODAL_Z_INDEX).toBeGreaterThan(APP_FOREGROUND_MODAL_Z_INDEX);
     expect(APP_COMMAND_PALETTE_Z_INDEX).toBeGreaterThan(APP_NESTED_MODAL_Z_INDEX);
+    expect(APP_APPLICATION_QUIT_MODAL_Z_INDEX).toBeGreaterThan(APP_COMMAND_PALETTE_Z_INDEX);
   });
 
   it('configures static Ant Design APIs with the same popup base', () => {

frontend/src/utils/overlayZIndex.ts

@@ -6,6 +6,7 @@ export const APP_POPUP_Z_INDEX = APP_OVERLAY_Z_INDEX_BASE + 9_000;
 export const APP_FOREGROUND_MODAL_Z_INDEX = APP_OVERLAY_Z_INDEX_BASE + 10_000;
 export const APP_NESTED_MODAL_Z_INDEX = APP_FOREGROUND_MODAL_Z_INDEX + 1_000;
 export const APP_COMMAND_PALETTE_Z_INDEX = APP_NESTED_MODAL_Z_INDEX + 1_000;
+export const APP_APPLICATION_QUIT_MODAL_Z_INDEX = APP_COMMAND_PALETTE_Z_INDEX + 1_000;
 
 export const configureAntdStaticOverlayLayer = (): void => {
   ConfigProvider.config({