OutputSelectionArgs.make_outputs was a comma-separated grin string parsed inside
libwallet via amount_from_hr_string. Move that parsing to the CLI boundary and
carry explicit nanogrin u64 amounts through the API and Context instead:
- OutputSelectionArgs.make_outputs: Option<String> -> Option<Vec<u64>>;
output_amounts() becomes a plain accessor, num_custom_outputs() uses len().
- The CLI (wallet_args) parses grin -> nanogrin per amount; ContractNewArgs and
ContractSetupArgs carry Vec<u64> and copy it through.
- Update the two tests that supplied make_outputs as a string.
Addresses PR #754 review (types.rs, wallet_args.rs).
jwinterm
f13ea7f01f