chore: add comment about tsoa incompatibility w/ zod

In case somebody is wondering why we have duplicate type definitions in
our code base.

Author: pheuberger

src/types/api.ts

@@ -1,5 +1,11 @@
 import type { HypercertMetadata } from "@hypercerts-org/sdk";
 
+/*
+ * The types in this file somewhat replicate the zod schemas we use in our controllers.
+ * Currently tsoa doesn't work with zod inferred types.
+ * See https://github.com/lukeautry/tsoa/issues/1256.
+ */
+
 /**
  * Interface for storing metadata on IPFS.
  */