Fetches a list of users and total balances grouped by Vault.
Sort key (see StakeSortType discriminants).
Sort direction: 0 = ascending, 1 = descending.
Position status filter (see StakeStatus discriminants).
Depositor wallet. Required by /lending_vaults/user/v2 (filter-only, no header fallback). Optional on legacy paths that read from the auth header.
OK