Function cross_account_confirm 

pub async fn cross_account_confirm(
    profile_id: ProfileId,
    source: ObjectRef,
    destination: ObjectRef,
    store: State<'_, ProfileStoreHandle>,
    confirm_cache: State<'_, ConfirmationCacheHandle>,
) -> Result<String, AppError>

Mint a one-time confirmation token for a large cross-account copy.

The frontend calls this command when object_copy returns a Validation { field: "confirmed_token" } error. The returned token must be passed back to object_copy as confirmed_token in the next call.

Tokens are single-use, scoped to exactly the (profile, source, destination) triple, and expire after 5 minutes.

Note on “heuristic check”

This command does not re-verify that a cross-account error actually occurred — the frontend is trusted to call it only after receiving the Validation error from object_copy. The token is harmless if the next object_copy succeeds via the server-side path (which returns ServerSideCopy without consulting the token).