修复注册流程不写入持久化登录态、注册失败500错误显示原始英文

Register组件缺少Login同款的keep-logged-in挂载副作用，导致注册产生的
新账号在下一次刷新时静默丢失会话（无报错、无跳转登录页）。
另外注册走原生WS {acc}协议而非REST，未接入CTRL_ERROR_TEXT_CN翻译表，
"internal error (500)"等错误会原样展示给用户。

第十轮最小粒度测试 Ch1-2 发现。

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/views/auth-onboarding-view.jsx

@@ -383,7 +383,7 @@ function VerificationButton({phone, scene = 'register', onChallenge, onError}) {
 // no phone-vs-username mode toggle. "Phone takes precedence" (per the spec text) is validation-only:
 // if a phone is filled it must be verified; the invite code is only required for a username-only
 // signup (matching the mock's original submit-time validation, now with real backend calls behind it).
-function Register({errorText, errorLevel, onImRegisterRequest}) {
+function Register({errorText, errorLevel, persist, onImRegisterRequest, onPersistenceChange}) {
   const [form, setForm] = React.useState({username: '', phone: '', code: '', password: '', invite: ''});
   const [challengeId, setChallengeId] = React.useState('');
   const [agreed, setAgreed] = React.useState(false);
@@ -392,6 +392,19 @@ function Register({errorText, errorLevel, onImRegisterRequest}) {
   const change = key => e => setForm({...form, [key]: e.target.value});
   const usingPhone = !!form.phone;
 
+  // Same silent "stay logged in" opt-in Login has (see its own copy of this effect for why there's
+  // no visible checkbox) -- missing here meant every account created by registering (as opposed to
+  // logging in) never had keep-logged-in/auth-token set, so handleLoginSuccessful() never persisted
+  // the session: the very next refresh silently lost myUserId with no redirect to the login page
+  // and no error, just a permanently empty messages-home shell. Every fresh registration hit this on
+  // its first reload.
+  React.useEffect(() => {
+    if (!persist) {
+      onPersistenceChange(true);
+    }
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, []);
+
   // onImRegisterRequest (tinode-web.jsx's handleImRegisterRequest -> a WS connect+createAccountBasic
   // chain) isn't awaited and doesn't return a promise -- on the username/invite-code path (no
   // verifyRegisterCode await ahead of it) `submit` returns and its `finally` clears `submitting`
@@ -795,7 +808,8 @@ export default function AuthOnboardingView({
       errorText={errorText} errorLevel={errorLevel} onLoginRequest={onLoginRequest} onPersistenceChange={onPersistenceChange} onError={onError} />;
     case 'enterprise-register': return <EnterpriseRegister />;
     case 'enterprise-feedback': return <EnterpriseFeedback />;
-    case 'register': return <Register errorText={errorText} errorLevel={errorLevel} onImRegisterRequest={onImRegisterRequest} />;
+    case 'register': return <Register errorText={errorText} errorLevel={errorLevel} persist={persist}
+      onImRegisterRequest={onImRegisterRequest} onPersistenceChange={onPersistenceChange} />;
     case 'reset': return <PasswordReset />;
     case 'identity-check': return <IdentityCheck authenticated={authenticated} hashParams={hashParams} />;
     case 'realname': return <Realname authenticated={authenticated} />;