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/pages/AttendanceLocation.tsx

@@ -134,9 +134,17 @@ export default function AttendanceLocation() {
           fillOpacity: 0.8,
         }).addTo(map);
 
-        marker.bindPopup(
-          `<strong>${loc.label}</strong><br>${loc.time}<br>Přesnost: ${Math.round(loc.accuracy)}m`,
+        const popupEl = document.createElement("div");
+        const strong = document.createElement("strong");
+        strong.textContent = loc.label;
+        popupEl.appendChild(strong);
+        popupEl.appendChild(document.createElement("br"));
+        popupEl.appendChild(document.createTextNode(loc.time));
+        popupEl.appendChild(document.createElement("br"));
+        popupEl.appendChild(
+          document.createTextNode(`Přesnost: ${Math.round(loc.accuracy)}m`),
         );
+        marker.bindPopup(popupEl);
 
         if (loc.accuracy > 0) {
           L.circle([loc.lat, loc.lng], {