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/context/AlertContext.tsx

@@ -57,7 +57,10 @@ export function AlertProvider({ children }: { children: ReactNode }) {
         { id, message, type: type as Alert["type"] },
       ]);
       if (duration > 0) {
-        const timeoutId = setTimeout(() => removeAlert(id), duration);
+        const timeoutId = setTimeout(() => {
+          timeoutsRef.current.delete(timeoutId);
+          removeAlert(id);
+        }, duration);
         timeoutsRef.current.add(timeoutId);
       }
       return id;

src/admin/context/AuthContext.tsx

@@ -268,6 +268,7 @@ export function AuthProvider({ children }: { children: ReactNode }) {
             login_token: loginToken,
             totp_code: code,
             remember_me: remember,
+            isBackup,
           }),
         });
         const data = await response.json();