feat: 统一验证码重发次数配置，优化相关逻辑和界面

tests/background-icloud.test.js

@@ -54,6 +54,7 @@ function extractFunction(name) {
 const bundle = [
   extractFunction('normalizeEmailGenerator'),
   extractFunction('getEmailGeneratorLabel'),
+  extractFunction('normalizeVerificationResendCount'),
   extractFunction('normalizePersistentSettingValue'),
   extractFunction('finalizeIcloudAliasAfterSuccessfulFlow'),
 ].join('\n');
@@ -66,6 +67,9 @@ const CLOUDFLARE_TEMP_EMAIL_GENERATOR = 'cloudflare-temp-email';
 const DEFAULT_LOCAL_CPA_STEP9_MODE = 'submit';
 const DEFAULT_HOTMAIL_REMOTE_BASE_URL = '';
 const DEFAULT_HOTMAIL_LOCAL_BASE_URL = 'http://127.0.0.1:17373';
+const DEFAULT_VERIFICATION_RESEND_COUNT = 4;
+const VERIFICATION_RESEND_COUNT_MIN = 0;
+const VERIFICATION_RESEND_COUNT_MAX = 20;
 const PERSISTED_SETTING_DEFAULTS = {
   mailProvider: '163',
   autoStepDelaySeconds: null,
@@ -175,6 +179,8 @@ test('normalizePersistentSettingValue handles icloud settings', () => {
   assert.equal(api.normalizePersistentSettingValue('icloudHostPreference', 'icloud.com'), 'icloud.com');
   assert.equal(api.normalizePersistentSettingValue('icloudHostPreference', 'bad-host'), 'auto');
   assert.equal(api.normalizePersistentSettingValue('autoDeleteUsedIcloudAlias', 1), true);
+  assert.equal(api.normalizePersistentSettingValue('verificationResendCount', '6'), 6);
+  assert.equal(api.normalizePersistentSettingValue('verificationResendCount', 99), 20);
   assert.equal(api.normalizePersistentSettingValue('cloudflareTempEmailReceiveMailbox', ' Forward@Example.com '), 'forward@example.com');
 });