feat: add Vitest and Playwright testing frameworks

Set up Vitest for unit/integration tests and Playwright for E2E tests; add configs, tests, and documentation

Co-authored-by: Moheeb Zara <[email protected]>

vitest.setup.ts

@@ -0,0 +1,46 @@
+import '@testing-library/jest-dom'
+import { expect, afterEach, vi } from 'vitest'
+import { cleanup } from '@testing-library/react'
+
+// Cleanup after each test
+afterEach(() => {
+  cleanup()
+})
+
+// Mock next/navigation
+vi.mock('next/navigation', () => ({
+  useRouter: () => ({
+    push: vi.fn(),
+    replace: vi.fn(),
+    prefetch: vi.fn(),
+    back: vi.fn(),
+  }),
+  usePathname: () => '/dashboard',
+  useSearchParams: () => new URLSearchParams(),
+}))
+
+// Mock next/image
+vi.mock('next/image', () => ({
+  default: (props: any) => {
+    // eslint-disable-next-line jsx-a11y/alt-text
+    return <img {...props} />
+  },
+}))
+
+// Suppress console errors in tests (optional)
+const originalError = console.error
+beforeAll(() => {
+  console.error = (...args: any[]) => {
+    if (
+      typeof args[0] === 'string' &&
+      args[0].includes('Warning: ReactDOM.render')
+    ) {
+      return
+    }
+    originalError.call(console, ...args)
+  }
+})
+
+afterAll(() => {
+  console.error = originalError
+})