fix: isolate settings and unify account controls with Code

tests/unit/main-layout-module-gate.test.tsx

@@ -44,6 +44,9 @@ vi.mock('@/components/layout/TitleBar', () => ({
     />
   ),
 }));
+vi.mock('@/components/account/StandaloneAccountDock', () => ({
+  StandaloneAccountDock: () => <div data-testid="standalone-account-dock-stub" />,
+}));
 
 function RouteContent() {
   routeRenderMock();
@@ -68,6 +71,16 @@ describe('MainLayout module isolation', () => {
     useSettingsStore.setState({ sidebarCollapsed: false });
   });
 
+  it.each(['/settings', '/settings/proxy'])('gives %s independent chrome without a project sidebar or collapse control', path => {
+    renderLayout(path);
+    expect(screen.getByTestId('settings-layout')).toBeVisible();
+    expect(screen.getByTestId('route-content')).toBeVisible();
+    expect(screen.queryByTestId('sidebar-stub')).not.toBeInTheDocument();
+    expect(screen.getByTestId('titlebar-stub')).toHaveAttribute('data-sidebar-controls', 'false');
+    expect(screen.getByTestId('titlebar-stub')).toHaveAttribute('data-page-title', '设置');
+    expect(screen.getByTestId('standalone-account-dock-stub')).toBeVisible();
+  });
+
   it('does not overlay the local project initialization gate on AI painting', () => {
     renderLayout('/image-canvas');