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/components/RegisterPage.tsx

@@ -47,9 +47,8 @@ export function RegisterPage() {
     e.preventDefault()
     setError('')
 
-    // 客户端强校验：长度>=8，包含大小写、数字、特殊字符，且两次一致
-    const strong = isStrongPassword(password)
-    if (!strong || password !== confirmPassword) {
+    // 使用 PasswordChecklist 的校验结果
+    if (!passwordValid) {
       setError(t('passwordNotMeetRequirements', language))
       return
     }
@@ -565,13 +564,3 @@ export function RegisterPage() {
     </div>
   )
 }
-
-// 本地密码强度校验（与 UI 规则一致）
-function isStrongPassword(pwd: string): boolean {
-  if (!pwd || pwd.length < 8) return false
-  const hasUpper = /[A-Z]/.test(pwd)
-  const hasLower = /[a-z]/.test(pwd)
-  const hasNumber = /\d/.test(pwd)
-  const hasSpecial = /[@#$%!&*?]/.test(pwd)
-  return hasUpper && hasLower && hasNumber && hasSpecial
-}