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/routes/admin/totp.ts

@@ -67,11 +67,11 @@ export default async function totpRoutes(
             400,
           );
         }
-        const isValid = OTPAuth.verify(
+        const verifyResult = OTPAuth.verify(
           user.totp_secret!,
           String(body.current_code),
         );
-        if (!isValid) {
+        if (!verifyResult.valid) {
           return error(reply, "Neplatný aktuální TOTP kód", 400);
         }
       } else {
@@ -153,8 +153,8 @@ export default async function totpRoutes(
         return error(reply, "2FA není aktivní", 400);
       }
 
-      const isValid = OTPAuth.verify(user.totp_secret, String(body.code));
-      if (!isValid) {
+      const verifyResult = OTPAuth.verify(user.totp_secret, String(body.code));
+      if (!verifyResult.valid) {
         return error(reply, "Neplatný TOTP kód", 400);
       }
 
@@ -308,7 +308,6 @@ export default async function totpRoutes(
           const isMatch = await bcrypt.compare(String(code), backupCodes[i]);
           if (isMatch) {
             matchIndex = i;
-            break;
           }
         }