Vesu protocol security review

In the increase_lever function, after a swap operation, the function swap returns a pair of values in_amount and out_amount. Due to differences between "swap exact in" and "swap exact out" operations, it is necessary to identify which amount corresponds to collateral and which to margin using the token address. The code assumes margin_amount > 0 and collateral_amount > 0 and proceeds to transfer the amounts and handle the delta accordingly. However, these assumptions are not verified before casting the amounts to i129_new. A similar issue exists in the increase_lever and decrease_lever functions when handling leverage swaps. Recommendation: Consider implementing a check to verify the sign of the amounts before casting them to i129_new.