feat: Enhance login flow with add-email and phone verification support

- Added support for the add-email page in the logging status module.
- Updated step 8 to handle phone-registered accounts during email verification.
- Implemented logic to submit add-email before polling for email verification codes.
- Enhanced tests for step 7 to detect username input as phone number and ignore hidden inputs.
- Improved step 8 to allow add-email handoff only when requested.
- Updated documentation to reflect changes in the login verification flow.

tests/background-logging-status-module.test.js

@@ -44,5 +44,6 @@ test('logging/status add-phone detection ignores step 2 phone-entry switch failu
     true
   );
   assert.equal(loggingStatus.getLoginAuthStateLabel('phone_verification_page'), '手机验证码页');
+  assert.equal(loggingStatus.getLoginAuthStateLabel('add_email_page'), '添加邮箱页');
   assert.equal(loggingStatus.getLoginAuthStateLabel('oauth_consent_page'), 'OAuth 授权页');
 });