fix: removed duplicated type declarations

tests/engine/PreloadContract.test.ts

@@ -0,0 +1,28 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+
+const exposeInMainWorld = vi.fn();
+
+vi.mock('electron', () => ({
+  contextBridge: {
+    exposeInMainWorld,
+  },
+  ipcRenderer: {
+    invoke: vi.fn(),
+    on: vi.fn(),
+    removeListener: vi.fn(),
+    once: vi.fn(),
+  },
+}));
+
+describe('preload contract', () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it('exports the electronAPI contract object and exposes it via contextBridge', async () => {
+    const preloadModule = await import('../../src/main/preload');
+
+    expect(preloadModule).toHaveProperty('electronAPI');
+    expect(exposeInMainWorld).toHaveBeenCalledWith('electronAPI', (preloadModule as { electronAPI: unknown }).electronAPI);
+  });
+});

tests/renderer/types/electronApiContract.test.ts

@@ -0,0 +1,9 @@
+import { describe, it, expectTypeOf } from 'vitest';
+import type { ElectronAPI as SharedElectronAPI } from '../../../src/main/shared/electronApi';
+import type { ElectronAPI as RendererElectronAPI } from '../../../src/renderer/types/electron';
+
+describe('Electron API type contract', () => {
+  it('keeps renderer and shared ElectronAPI contracts in sync', () => {
+    expectTypeOf<RendererElectronAPI>().toEqualTypeOf<SharedElectronAPI>();
+  });
+});