feat: use unified compact title bar on windows and linux

Co-authored-by: rfc1437 <774975+rfc1437@users.noreply.github.com>

tests/engine/mainStartup.test.ts

@@ -6,6 +6,126 @@ describe('main bootstrap preview behavior', () => {
     vi.resetModules();
   });
 
+  it.each(['win32', 'linux'])('uses compact unified window decorations on %s', async (platform) => {
+    const originalPlatform = process.platform;
+    Object.defineProperty(process, 'platform', { value: platform });
+
+    const mockApp = {
+      name: 'bDS',
+      whenReady: vi.fn(() => Promise.resolve()),
+      on: vi.fn(),
+      quit: vi.fn(),
+    };
+
+    const browserWindowCalls: any[] = [];
+    class BrowserWindowMock {
+      static getAllWindows = vi.fn(() => [{ id: 1 }]);
+
+      loadURL = vi.fn();
+      loadFile = vi.fn();
+      on = vi.fn();
+      isDestroyed = vi.fn(() => false);
+      webContents = {
+        on: vi.fn(),
+        send: vi.fn(),
+        openDevTools: vi.fn(),
+        toggleDevTools: vi.fn(),
+      };
+
+      constructor(options: any) {
+        browserWindowCalls.push(options);
+      }
+    }
+
+    vi.doMock('electron', () => ({
+      app: mockApp,
+      BrowserWindow: BrowserWindowMock,
+      Menu: {
+        buildFromTemplate: vi.fn(() => ({})),
+        setApplicationMenu: vi.fn(),
+      },
+      ipcMain: {
+        on: vi.fn(),
+        handle: vi.fn(),
+        removeHandler: vi.fn(),
+      },
+      protocol: {
+        registerSchemesAsPrivileged: vi.fn(),
+        handle: vi.fn(),
+      },
+      net: {
+        fetch: vi.fn(),
+      },
+      shell: {
+        openExternal: vi.fn(),
+        openPath: vi.fn(),
+      },
+    }));
+
+    class MockPreviewServer {
+      start = vi.fn().mockResolvedValue(4123);
+      stop = vi.fn().mockResolvedValue(undefined);
+      getBaseUrl = vi.fn(() => 'http://127.0.0.1:4123');
+    }
+
+    vi.doMock('../../src/main/engine/PreviewServer', () => ({
+      PreviewServer: MockPreviewServer,
+    }));
+
+    vi.doMock('../../src/main/database', () => ({
+      getDatabase: vi.fn(() => ({
+        initializeLocal: vi.fn().mockResolvedValue(undefined),
+        close: vi.fn().mockResolvedValue(undefined),
+        getLocal: vi.fn(() => ({
+          select: vi.fn(() => ({
+            from: vi.fn(() => ({
+              where: vi.fn(() => ({
+                get: vi.fn().mockResolvedValue(null),
+              })),
+            })),
+          })),
+        })),
+        getDataPaths: vi.fn(() => ({ database: '/tmp/mock.db' })),
+      })),
+    }));
+
+    vi.doMock('../../src/main/ipc', () => ({
+      registerIpcHandlers: vi.fn(),
+      registerChatHandlers: vi.fn(),
+      initializeChatHandlers: vi.fn(),
+      cleanupChatHandlers: vi.fn().mockResolvedValue(undefined),
+    }));
+
+    vi.doMock('../../src/main/database/schema', () => ({
+      media: {},
+    }));
+
+    vi.doMock('drizzle-orm', () => ({
+      eq: vi.fn(),
+    }));
+
+    vi.doMock('../../src/main/engine/MediaEngine', () => ({
+      getMediaEngine: vi.fn(() => ({
+        getThumbnailPaths: vi.fn().mockResolvedValue({ small: null }),
+      })),
+    }));
+
+    await import('../../src/main/main');
+    await new Promise((resolve) => setTimeout(resolve, 0));
+
+    expect(browserWindowCalls[0]).toEqual(expect.objectContaining({
+      titleBarStyle: 'hidden',
+      titleBarOverlay: {
+        color: '#252526',
+        symbolColor: '#cccccc',
+        height: 34,
+      },
+      autoHideMenuBar: true,
+    }));
+
+    Object.defineProperty(process, 'platform', { value: originalPlatform });
+  });
+
   it('starts preview server during app startup', async () => {
     const mockApp = {
       name: 'bDS',