Email delivery failures and PDF generation errors now show a permanent
warning/error toast that requires manual dismissal, so users cannot
accidentally miss critical action-blocking feedback.
- ToastHelper: WarningPermanent TempData key + Warning/WarningPermanent
extension methods on both ITempDataDictionary and Controller
- SetNotificationResultToast: NotificationStatus.Failed now uses
ToastWarningPermanent (previously auto-dismissed in 5 s)
- InvoicesController.Send: TempData["Warning"] → TempData["WarningPermanent"]
when PDF generation or email dispatch fails
- InvoicesController.DownloadPdf: TempData["Error"] → TempData["ErrorPermanent"]
with the actual exception message so root cause is visible
- _Layout.cshtml: WarningPermanent hidden div
- toast-notifications.js: WarningPermanent handler (timeOut: 0)
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
spouliot