Align fullscreen return button with project actions

tests/unit/title-bar.test.tsx

@@ -24,6 +24,7 @@ describe('TitleBar platform behavior', () => {
   beforeEach(() => {
     invokeIpcMock.mockReset();
     invokeIpcMock.mockResolvedValue(false);
+    vi.mocked(window.electron.ipcRenderer.on).mockReset();
     useSettingsStore.setState({ sidebarCollapsed: false, classroomSidebarWidth: 171 });
   });
 
@@ -84,7 +85,7 @@ describe('TitleBar platform behavior', () => {
 
     expect(container.querySelector('.drag-region')).toBeInTheDocument();
     expect(screen.queryByTitle('Minimize')).not.toBeInTheDocument();
-    expect(invokeIpcMock).not.toHaveBeenCalled();
+    expect(invokeIpcMock).toHaveBeenCalledWith('window:isFullScreen');
   });
 
   it('aligns the classroom title bar with one project sidebar and no duplicate branding', () => {
@@ -108,6 +109,50 @@ describe('TitleBar platform behavior', () => {
     expect(screen.getByTestId('titlebar-sidebar-toggle')).toHaveClass('right-2');
   });
 
+  it('aligns fullscreen return with project buttons and restores native window-control space on exit', async () => {
+    window.electron.platform = 'darwin';
+    invokeIpcMock.mockResolvedValue(true);
+    const unsubscribe = vi.fn();
+    let notify: (...args: unknown[]) => void = () => {};
+    vi.mocked(window.electron.ipcRenderer.on).mockImplementation((channel, callback) => {
+      expect(channel).toBe('window:fullscreen-changed');
+      notify = callback;
+      return unsubscribe;
+    });
+    const { unmount } = render(<TitleBar integrated workspaceLayout />);
+    const navigation = screen.getByTestId('classroom-titlebar-navigation');
+    await waitFor(() => expect(navigation).toHaveClass('pl-3'));
+    act(() => notify(false));
+    expect(navigation).toHaveClass('pl-[88px]');
+    act(() => notify(true));
+    expect(navigation).toHaveClass('pl-3');
+    unmount();
+    expect(unsubscribe).toHaveBeenCalledOnce();
+  });
+
+  it('keeps a native fullscreen transition when an older initial query resolves later', async () => {
+    window.electron.platform = 'darwin';
+    let resolveQuery: (value: boolean) => void = () => {};
+    invokeIpcMock.mockReturnValue(new Promise<boolean>((resolve) => { resolveQuery = resolve; }));
+    let notify: (...args: unknown[]) => void = () => {};
+    vi.mocked(window.electron.ipcRenderer.on).mockImplementation((_channel, callback) => {
+      notify = callback;
+      return vi.fn();
+    });
+    render(<TitleBar integrated workspaceLayout />);
+    act(() => notify(true));
+    await act(async () => resolveQuery(false));
+    expect(screen.getByTestId('classroom-titlebar-navigation')).toHaveClass('pl-3');
+  });
+
+  it('keeps the native safe inset when an older preload rejects fullscreen events', () => {
+    window.electron.platform = 'darwin';
+    vi.mocked(window.electron.ipcRenderer.on).mockImplementation(() => { throw new Error('Invalid IPC channel'); });
+    render(<TitleBar integrated workspaceLayout />);
+    expect(screen.getByTestId('classroom-titlebar-navigation')).toHaveClass('pl-[88px]');
+    expect(invokeIpcMock).not.toHaveBeenCalled();
+  });
+
   it('renders the painting title bar as a transparent overlay with the logo at the window edge', () => {
     window.electron.platform = 'darwin';
 
@@ -214,7 +259,7 @@ describe('TitleBar platform behavior', () => {
 
   it.each([
     ['darwin', 168, 168, 'pl-[88px]'],
-    ['win32', 128, 88, 'pl-2'],
+    ['win32', 128, 88, 'pl-3'],
   ] as const)('keeps both %s navigation controls outside the conversation header at narrow and collapsed widths', (platform, narrowWidth, collapsedWidth, insetClass) => {
     window.electron.platform = platform;
     useSettingsStore.setState({ classroomSidebarWidth: 128 });