feat: more cleanup work in UI

tests/setup.ts

@@ -4,6 +4,88 @@
  */
 
 import { vi, beforeEach, afterEach } from 'vitest';
+import '@testing-library/jest-dom/vitest';
+
+// Mock localStorage for Zustand persist middleware
+const localStorageMock = (() => {
+  let store: Record<string, string> = {};
+  return {
+    getItem: vi.fn((key: string) => store[key] || null),
+    setItem: vi.fn((key: string, value: string) => {
+      store[key] = value;
+    }),
+    removeItem: vi.fn((key: string) => {
+      delete store[key];
+    }),
+    clear: vi.fn(() => {
+      store = {};
+    }),
+    get length() {
+      return Object.keys(store).length;
+    },
+    key: vi.fn((index: number) => Object.keys(store)[index] || null),
+  };
+})();
+
+Object.defineProperty(globalThis, 'localStorage', {
+  value: localStorageMock,
+  writable: true,
+});
+
+// Mock window.electronAPI for renderer tests
+Object.defineProperty(globalThis, 'window', {
+  value: {
+    electronAPI: {
+      posts: {
+        create: vi.fn(),
+        update: vi.fn(),
+        delete: vi.fn(),
+        get: vi.fn(),
+        getAll: vi.fn(),
+        getByStatus: vi.fn(),
+        publish: vi.fn(),
+        unpublish: vi.fn(),
+        rebuildFromFiles: vi.fn(),
+        search: vi.fn(),
+        filter: vi.fn(),
+        getTags: vi.fn(),
+        getCategories: vi.fn(),
+        getByYearMonth: vi.fn(),
+        getLinksTo: vi.fn(),
+        getLinkedBy: vi.fn(),
+        rebuildLinks: vi.fn(),
+      },
+      media: {
+        import: vi.fn(),
+        importDialog: vi.fn(),
+        update: vi.fn(),
+        delete: vi.fn(),
+        get: vi.fn(),
+        getAll: vi.fn(),
+        rebuildFromFiles: vi.fn(),
+        getThumbnail: vi.fn(),
+        regenerateThumbnails: vi.fn(),
+      },
+      sync: {
+        configure: vi.fn(),
+        start: vi.fn(),
+        getStatus: vi.fn(),
+        isConfigured: vi.fn(),
+        getPendingCount: vi.fn(),
+        getLog: vi.fn(),
+        stopAutoSync: vi.fn(),
+      },
+      tasks: {
+        getAll: vi.fn(),
+        getRunning: vi.fn(),
+        cancel: vi.fn(),
+        clearCompleted: vi.fn(),
+      },
+      on: vi.fn(() => () => {}),
+    },
+  },
+  writable: true,
+});
 
 // Mock Electron app module
 vi.mock('electron', () => ({