fix(web): unify password validation logic in RegisterPage (#943)

Remove duplicate password validation logic to ensure consistency.
Changes:
- Remove custom isStrongPassword function (RegisterPage.tsx:569-576)
- Use PasswordChecklist validation result (passwordValid state) instead
- Add comprehensive test suite with 28 test cases
- Configure Vitest with jsdom environment and setup file
Test Coverage:
- Password validation rules (length, uppercase, lowercase, number, special chars)
- Special character consistency (/[@#$%!&*?]/)
- Edge cases and boundary conditions
- Refactoring consistency verification
All 78 tests passing (25 + 25 + 28).
Co-authored-by: tinkle-community <tinklefund@gmail.com>

web/src/test/setup.ts

@@ -0,0 +1,32 @@
+import '@testing-library/jest-dom'
+import { beforeAll, afterEach } from 'vitest'
+
+// Mock localStorage
+const localStorageMock = {
+  getItem: (key: string) => {
+    return localStorageMock._store[key] || null
+  },
+  setItem: (key: string, value: string) => {
+    localStorageMock._store[key] = value
+  },
+  removeItem: (key: string) => {
+    delete localStorageMock._store[key]
+  },
+  clear: () => {
+    localStorageMock._store = {}
+  },
+  _store: {} as Record<string, string>,
+}
+
+// Setup before all tests
+beforeAll(() => {
+  Object.defineProperty(window, 'localStorage', {
+    value: localStorageMock,
+    writable: true,
+  })
+})
+
+// Clean up after each test
+afterEach(() => {
+  localStorageMock.clear()
+})