React SDK useConsume uses proxy signer, fails recipient verification in custom scripts

## Context

Reported by multiple builders during Miden Day (agentic template feedback).

`useConsume` from the React SDK uses a proxy signer account created by `MidenFiSignerProvider`, not the real wallet account. Any note script that verifies `active_account::get_id()` fails because the consuming account ID doesn't match the intended recipient.

The React SDK (WebClient) can execute custom note scripts but uses the wrong account. The wallet adapter has the right account but can't execute custom scripts. These two worlds are disconnected.