PostgreSQL type -> Swagger 2.0 schema mapping (mirrors PostgREST OpenAPI.hs:59-115).
Two modes: schema/2 for column/definition/body properties, query_param/2
for RPC GET query parameters (arrays/json collapse to string).
Summary
Functions
Decode a column default expression to a JSON value, or :omit when there is none.
Query-param mode mapping (RPC GET parameters).
Schema-mode mapping (definition properties, RPC POST body properties).