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/FormField.tsx

@@ -1,4 +1,10 @@
-import type { CSSProperties, ReactNode } from "react";
+import {
+  type CSSProperties,
+  type ReactNode,
+  isValidElement,
+  cloneElement,
+  useId,
+} from "react";
 
 interface FormFieldProps {
   label: ReactNode;
@@ -15,13 +21,22 @@ export default function FormField({
   required,
   style,
 }: FormFieldProps) {
+  const generatedId = useId();
+  const childProps = isValidElement(children)
+    ? (children.props as Record<string, unknown>)
+    : null;
+  const childId = childProps?.id ? String(childProps.id) : generatedId;
+  const childWithId = isValidElement(children)
+    ? cloneElement(children, { id: childId } as React.Attributes)
+    : children;
+
   return (
     <div className="admin-form-group" style={style}>
-      <label className="admin-form-label">
+      <label className="admin-form-label" htmlFor={childId}>
         {label}
         {required && <span className="admin-form-required"> *</span>}
       </label>
-      {children}
+      {childWithId}
       {error && <span className="admin-form-error">{error}</span>}
     </div>
   );