Catalog entry.
Flat input.
The request.
The input is validated with the merged schema first; values are then sent
in their wire (input) form: :param segments encodeURIComponent-encoded,
a * wildcard encoded per segment with / kept, query scalars as strings
and arrays as repeated keys, and body fields as JSON.
CatalogClientError with status 0 and the Zod issues when the input is invalid.
Turn one flat input object into a request for an entry.