fix: security, validation, and data integrity fixes across 53 files

- Auth: HS256 algorithm restriction on JWT verify, timing-safe bcrypt
  for inactive/locked users, locked_until check in loadAuthData, TOTP
  fixes (async bcrypt, BigInt conversion, future-code counter fix)
- Validation: Zod enums for leave_type/status, numeric transforms on
  foreign keys, VAT 0% coercion fix (Number(v)||21 → v!=null checks)
- Permissions: requirePermission on attendance PUT, attendance_users
  and project_logs access checks, trips users filtered by trips.record
- Prisma queries: fixed roles.is:{OR} pattern (doesn't work on to-one
  relations), attendance_users now filters by attendance.record only
- Transactions: wrapped deleteOrder, createOrder, updateUser, deleteUser,
  duplicateOffer, bulkCreateAttendance, createLeave, scope-templates,
  leave-requests, company-settings, profile updates
- Frontend: mountedRef reset in useListData, blob URL cleanup on unmount,
  null checks on date fields, AdminDatePicker min/max for HH:mm
- Security headers: COOP, CORP, CSP frame-ancestors/form-action/base-uri
- Other: exchange-rate cache TTL, invoice-alert midnight comparison fix,
  numbering.service releaseSequence no-op, nas-offers filename sanitize,
  Content-Disposition header injection fix, mojibake Czech strings

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

src/admin/pages/OfferDetail.tsx

@@ -323,6 +323,7 @@ export default function OfferDetail() {
   const [customerOrderNumber, setCustomerOrderNumber] = useState("");
   const [orderAttachment, setOrderAttachment] = useState<File | null>(null);
   const [pdfLoading, setPdfLoading] = useState(false);
+  const blobTimeoutsRef = useRef<ReturnType<typeof setTimeout>[]>([]);
   const [companySettings, setCompanySettings] = useState<{
     default_currency: string;
     default_vat_rate: number;
@@ -341,6 +342,12 @@ export default function OfferDetail() {
 
   useModalLock(showOrderModal);
 
+  useEffect(() => {
+    return () => {
+      blobTimeoutsRef.current.forEach(clearTimeout);
+    };
+  }, []);
+
   useEffect(() => {
     apiFetch(`${API_BASE}/company-settings`)
       .then((r) => r.json())
@@ -829,7 +836,8 @@ export default function OfferDetail() {
       const blob = await response.blob();
       const url = URL.createObjectURL(blob);
       if (newWindow) newWindow.location.href = url;
-      setTimeout(() => URL.revokeObjectURL(url), 60000);
+      const timeoutId = setTimeout(() => URL.revokeObjectURL(url), 60000);
+      blobTimeoutsRef.current.push(timeoutId);
     } catch {
       newWindow?.close();
       alert.error("Chyba při generování PDF");