fix(frontend): preserve callback recovery state

frontend/src/views/auth/LinuxDoCallbackView.vue

@@ -603,6 +603,14 @@ async function finalizePendingAccountResponse(completion: LinuxDoPendingActionRe
     return
   }
 
+  if (completion.auth_result === 'pending_session') {
+    needsInvitation.value = false
+    needsAdoptionConfirmation.value = false
+    isProcessing.value = false
+    persistPendingAuthSession(redirect)
+    return
+  }
+
   await finalizeCompletion(completion, redirect)
 }
 
@@ -612,9 +620,9 @@ async function handleSubmitInvitation() {
 
   isSubmitting.value = true
   try {
-    const tokenData = legacyPendingOAuthToken.value
+    const completion: LinuxDoPendingActionResponse = legacyPendingOAuthToken.value
       ? (
-          await apiClient.post<OAuthTokenResponse>('/auth/oauth/linuxdo/complete-registration', {
+          await apiClient.post<LinuxDoPendingActionResponse>('/auth/oauth/linuxdo/complete-registration', {
             pending_oauth_token: legacyPendingOAuthToken.value,
             invitation_code: invitationCode.value.trim(),
             ...serializeAdoptionDecision(currentAdoptionDecision())
@@ -624,10 +632,7 @@ async function handleSubmitInvitation() {
           invitationCode.value.trim(),
           currentAdoptionDecision()
         )
-    persistOAuthTokenContext(tokenData)
-    await authStore.setToken(tokenData.access_token)
-    appStore.showSuccess(t('auth.loginSuccess'))
-    await router.replace(redirectTo.value)
+    await finalizePendingAccountResponse(completion)
   } catch (e: unknown) {
     const err = e as { message?: string; response?: { data?: { message?: string } } }
     invitationError.value =