Add TOTP authenticator support for Bambu Cloud login (fixes #182)

TOTP (Two-Factor Authentication):
- Detect TOTP vs email verification from Bambu API loginType response
- Use dedicated TFA endpoint on bambulab.com (not api.bambulab.com)
- Include browser-like headers to bypass Cloudflare protection
- Extract token from JSON response or cookies
- Frontend shows appropriate messages for each verification type
- Added i18n translations for TOTP UI (en, de, ja)

Closes #182

frontend/src/api/client.ts

@@ -769,6 +769,8 @@ export interface CloudLoginResponse {
   success: boolean;
   needs_verification: boolean;
   message: string;
+  verification_type?: 'email' | 'totp' | null;
+  tfa_key?: string | null;
 }
 
 export interface SlicerSetting {
@@ -2620,10 +2622,10 @@ export const api = {
       method: 'POST',
       body: JSON.stringify({ email, password, region }),
     }),
-  cloudVerify: (email: string, code: string) =>
+  cloudVerify: (email: string, code: string, tfaKey?: string) =>
     request<CloudLoginResponse>('/cloud/verify', {
       method: 'POST',
-      body: JSON.stringify({ email, code }),
+      body: JSON.stringify({ email, code, tfa_key: tfaKey }),
     }),
   cloudSetToken: (access_token: string) =>
     request<CloudAuthStatus>('/cloud/token', {

frontend/src/i18n/locales/de.ts

@@ -1656,7 +1656,9 @@ export default {
       regionGlobal: 'Global',
       regionChina: 'China',
       verificationCode: 'Bestätigungscode',
+      totpCode: 'Authenticator-Code',
       checkEmail: 'Prüfen Sie Ihre E-Mail ({{email}}) für einen 6-stelligen Code',
+      enterTotpHint: 'Geben Sie den 6-stelligen Code aus Ihrer Authenticator-App ein',
       accessToken: 'Zugriffstoken',
       accessTokenHint: 'Fügen Sie Ihr Bambu Lab Zugriffstoken ein (aus Bambu Studio)',
       back: 'Zurück',
@@ -1668,6 +1670,7 @@ export default {
       toast: {
         loggedIn: 'Erfolgreich angemeldet',
         codeSent: 'Bestätigungscode an Ihre E-Mail gesendet',
+        enterTotp: 'Geben Sie den Code aus Ihrer Authenticator-App ein',
         tokenSet: 'Token erfolgreich gesetzt',
       },
     },

frontend/src/i18n/locales/en.ts

@@ -1656,7 +1656,9 @@ export default {
       regionGlobal: 'Global',
       regionChina: 'China',
       verificationCode: 'Verification Code',
+      totpCode: 'Authenticator Code',
       checkEmail: 'Check your email ({{email}}) for a 6-digit code',
+      enterTotpHint: 'Enter the 6-digit code from your authenticator app',
       accessToken: 'Access Token',
       accessTokenHint: 'Paste your Bambu Lab access token (from Bambu Studio)',
       back: 'Back',
@@ -1668,6 +1670,7 @@ export default {
       toast: {
         loggedIn: 'Logged in successfully',
         codeSent: 'Verification code sent to your email',
+        enterTotp: 'Enter code from your authenticator app',
         tokenSet: 'Token set successfully',
       },
     },

frontend/src/i18n/locales/ja.ts

@@ -731,7 +731,9 @@ export default {
     regionGlobal: 'グローバル',
     regionChina: '中国',
     verificationCode: '認証コード',
+    totpCode: '認証アプリコード',
     checkEmail: 'メール ({{email}}) に届いた6桁のコードを入力してください',
+    enterTotpHint: '認証アプリの6桁のコードを入力してください',
     accessToken: 'アクセストークン',
     accessTokenHint: 'Bambu Labのアクセストークンを貼り付け（Bambu Studioから取得）',
     login: 'ログイン',
@@ -741,6 +743,7 @@ export default {
     loginWithEmail: 'メールでログイン',
     loggedIn: 'ログインしました',
     verificationSent: '認証コードをメールに送信しました',
+    enterTotp: '認証アプリのコードを入力してください',
     tokenSet: 'トークンを設定しました',
     loggedOut: 'ログアウトしました',
     logout: 'ログアウト',

frontend/src/pages/ProfilesPage.tsx

@@ -117,6 +117,8 @@ function LoginForm({ onSuccess, t }: { onSuccess: () => void; t: TFunction }) {
   const [code, setCode] = useState('');
   const [token, setToken] = useState('');
   const [region, setRegion] = useState('global');
+  const [verificationType, setVerificationType] = useState<'email' | 'totp' | null>(null);
+  const [tfaKey, setTfaKey] = useState<string | null>(null);
 
   const loginMutation = useMutation({
     mutationFn: () => api.cloudLogin(email, password, region),
@@ -125,7 +127,13 @@ function LoginForm({ onSuccess, t }: { onSuccess: () => void; t: TFunction }) {
         showToast(t('profiles.login.toast.loggedIn'));
         onSuccess();
       } else if (result.needs_verification) {
-        showToast(t('profiles.login.toast.codeSent'));
+        setVerificationType(result.verification_type || 'email');
+        setTfaKey(result.tfa_key || null);
+        if (result.verification_type === 'totp') {
+          showToast(t('profiles.login.toast.enterTotp'));
+        } else {
+          showToast(t('profiles.login.toast.codeSent'));
+        }
         setStep('code');
       } else {
         showToast(result.message, 'error');
@@ -135,7 +143,7 @@ function LoginForm({ onSuccess, t }: { onSuccess: () => void; t: TFunction }) {
   });
 
   const verifyMutation = useMutation({
-    mutationFn: () => api.cloudVerify(email, code),
+    mutationFn: () => api.cloudVerify(email, code, tfaKey || undefined),
     onSuccess: (result) => {
       if (result.success) {
         showToast(t('profiles.login.toast.loggedIn'));
@@ -217,8 +225,14 @@ function LoginForm({ onSuccess, t }: { onSuccess: () => void; t: TFunction }) {
 
           {step === 'code' && (
             <div>
-              <label className="block text-sm text-bambu-gray mb-1">{t('profiles.login.verificationCode')}</label>
-              <p className="text-xs text-bambu-gray mb-2">{t('profiles.login.checkEmail', { email })}</p>
+              <label className="block text-sm text-bambu-gray mb-1">
+                {verificationType === 'totp' ? t('profiles.login.totpCode') : t('profiles.login.verificationCode')}
+              </label>
+              <p className="text-xs text-bambu-gray mb-2">
+                {verificationType === 'totp'
+                  ? t('profiles.login.enterTotpHint')
+                  : t('profiles.login.checkEmail', { email })}
+              </p>
               <input
                 type="text"
                 value={code}