feat: 增强步骤 3 的手机号注册逻辑，确保手机号身份优先处理并添加相关测试用例

tests/sidepanel-icloud-provider.test.js

@@ -512,6 +512,7 @@ function updateAccountRunHistorySettingsUI() {}
 function updatePhoneVerificationSettingsUI() {}
 function updatePanelModeUI() {}
 function updateMailProviderUI() { calls.push({ target: selectIcloudTargetMailboxType.value, provider: selectIcloudForwardMailProvider.value }); }
+function renderSub2ApiGroupOptions() {}
 function isLuckmailProvider() { return false; }
 function updateButtonStates() {}
 ${bundle}