security: fix all Medium findings from FLAWS_REPORT audit

- Auth: TOTP replay protection with counter tracking, constant-time
  backup code comparison, atomic lockout increment, per-token logout
- Invoices/PDFs: net-based VAT calculation, dangerous URL scheme
  stripping in cleanQuillHtml, orders-pdf error handling
- Orders: reject item changes on status transition, cascading
  delete cleanup, take:1 with orderBy
- Projects: atomic rename collision handling, MIME/extension
  validation, empty customer name rejection
- Attendance: Czech public holiday awareness in frontend fund
  calculation, leave_hours 0 handling, invalid date NaN guard,
  bounded per-month queries in workfund
- Users/Admin: profile audit logging + password validation, session
  revocation guard, session ID validation, dashboard DB aggregation,
  soft-deleted record protection in scope templates
- Frontend: FormField label linkage, Pagination ARIA, error
  handling in OrderConfirmationModal, 401 propagation, GPS emoji
  hidden from screen readers, table sort state fix, geolocation
  race/abort cleanup, Leaflet popup DOM safety, Vehicles toggleActive
  minimal body, CompanySettings ref mutation fix, OfferDetail unlock
  abort, AttendanceBalances combined fetches
- Utils: env validation, Puppeteer concurrency mutex, invoice alert
  cron cleanup on shutdown, body limit alignment, TOTP error logging,
  trustProxy from env, symlink rejection, rate cache Map usage

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/admin/components/OrderConfirmationModal.tsx

@@ -1,5 +1,6 @@
 import { useState, useCallback } from "react";
 import { motion, AnimatePresence } from "framer-motion";
+import { useAlert } from "../context/AlertContext";
 
 interface ConfirmationItem {
   description: string;
@@ -33,6 +34,7 @@ export default function OrderConfirmationModal({
   defaultVatRate,
   applyVat,
 }: OrderConfirmationModalProps) {
+  const alert = useAlert();
   const [step, setStep] = useState<"choose" | "edit">("choose");
   const [lang, setLang] = useState<string>("cs");
   const [applyVatState, setApplyVatState] = useState(applyVat);
@@ -43,6 +45,9 @@ export default function OrderConfirmationModal({
     setLoading(true);
     try {
       await onGenerate(lang, applyVatState, undefined);
+    } catch (err) {
+      console.error("Chyba při generování potvrzení:", err);
+      alert.error("Nepodařilo se vygenerovat potvrzení");
     } finally {
       setLoading(false);
       setStep("choose");
@@ -54,6 +59,9 @@ export default function OrderConfirmationModal({
     setLoading(true);
     try {
       await onGenerate(lang, applyVatState, items);
+    } catch (err) {
+      console.error("Chyba při generování potvrzení:", err);
+      alert.error("Nepodařilo se vygenerovat potvrzení");
     } finally {
       setLoading(false);
       setStep("choose");