Max add option

[agualis]

We removed the old Maximize option after refactoring to explicit SDK Proportional handlers.

It was using calculateProportionalAmounts helper form the SDK which does not work nicely with the explicit SDK Proportional handlers (as they expect exact bpt out instead of tokens in).

Users can always maximize clicking the wallet icon, although the amounts will go over the balance if they click the wrong one.

This ticket is about exploring better UX for maximizing (check the old optimize code in useProportionalInputs for ideas).

[garethfuller]

cc @uiuxxx