test: add vitest config and unit tests

src/__tests__/setup.ts

@@ -0,0 +1,14 @@
+import { vi } from 'vitest'
+
+// Mock Element Plus components globally
+vi.mock('element-plus', () => ({
+  ElMessage: {
+    success: vi.fn(),
+    error: vi.fn(),
+    warning: vi.fn(),
+    info: vi.fn(),
+  },
+  ElMessageBox: {
+    confirm: vi.fn().mockResolvedValue('confirm'),
+  },
+}))