feat(security): harden the API, trust Hiboutik for deletions, lock syncs (#3)

src/utils/sync.ts

@@ -2,6 +2,9 @@ import { Logger } from '@nestjs/common';
 
 /**
  * Runs `action` on each item, one at a time: a failing item is logged and skipped, the others are still processed.
+ * @param items
+ * @param action
+ * @param logger
  * @param describe label of an item in the error log, e.g. "Hiboutik brand 12".
  * @returns the number of failed items.
  */