Ordering by values in union fields

We can do filtering by values in union fields, but not ordering.

So assume we had something like

type Starting @variant {
  started: Int!
  money: Int!
  }
  
 type Voting @variant {
  time: Int!
  }

union ProposalState = Starting | Voting

type  Proposal @entity {
  my_state_fied: ProposalState
}

Then we would get something like

enum ProposalStateOrderByInput {
  Starting_started_ASC
  Starting_started_DESC
  Starting_money_ASC
  Starting_money_DESC
  Voting_time_ASC
  Voting_time_DESC
}

Should obviously generalize to arbitrary nesting of union types, but idea is the same, in the end you get one big enum with finite number of paths.

PostgreSQL itself seems well equipped to execute such ordering also

https://stackoverflow.com/questions/25967778/order-by-json-data-type-postgres

Trace the existing union-field filtering and order-by generation paths first, then review how PostgreSQL JSON ordering could support nested union values. Done means generating finite order-by enum paths for union fields, including arbitrary nesting, and applying the selected ascending or descending ordering correctly.