Typed interface calls cannot return multiple values

Typed interface (dot-call) methods support a single return value:

interface IIdleCreditVault where
  function prepareStopEpochWithApr0(Uint256) returns (Uint256, Uint256)
end
...
let (a, b) ← strategy.prepareStopEpochWithApr0 x
-- error: interface call 'IIdleCreditVault.prepareStopEpochWithApr0' returns multiple values; typed dot calls currently support one return value

Pareto's stopEpoch calls two such methods (prepareStopEpochWithApr0, previewLossAdjustedWithdrawFunds, both (uint256, uint256)). The only compiling encoding is a name-keyed linked_externals external f(Uint256) -> (Uint256, Uint256) with callExternal, which loses the target address (the strategy) in the compilation model.

Ask: allow tuple destructuring of typed interface calls with static multi-word returns (the ABI-frame lowering tracked in #1982 covers the dynamic case; two static words should not need it).

Closure-side tracking: audit/VERITY-GAPS.md G14.

Start with the typed interface call example and the two Pareto methods named in the issue, then read the ABI-frame lowering work tracked in #1982. Check audit/VERITY-GAPS.md for G14 and trace how static two-word returns are compiled. Done means tuple destructuring works for these calls without losing the strategy target address.