fix(client): correct return inventory carton paging and label printing

src/api/types.ts

@@ -30,3 +30,13 @@ export function isApiEnvelope(value: unknown): value is ApiEnvelope<unknown> {
   const record = value as Record<string, unknown>
   return typeof record.code === 'string' && typeof record.message === 'string' && 'data' in record
 }
+
+// Security failures have no business data, unlike successful API responses.
+export function isApiFailure(value: unknown): value is Omit<ApiEnvelope<never>, 'data'> {
+  if (!value || typeof value !== 'object') return false
+  const record = value as Record<string, unknown>
+  return typeof record.code === 'string' && record.code !== '200'
+    && typeof record.message === 'string'
+    && (record.requestId == null || typeof record.requestId === 'string')
+    && (record.traceId == null || typeof record.traceId === 'string')
+}