Verify if transfer allowances are valid and fix if needed

From the report:

> If I create a transfer allowance for quantity = 1 and uses = 1 and then use FetchAllowances, it shows quantity Infinity for the new allowance. uses correctly shows 1 but there’s no usesSpent property and it allows me to use the allowance more than once. There’s also no quantitySpent property and it allows me to transfer any quantity.

Start by tracing the FetchAllowances path and the transfer-allowance usage flow described in the report. Verify how quantity and uses are represented and enforced; done means fetched allowances expose the relevant spent values and cannot be reused or transferred beyond their limits.

Written by the indexing model from the issue text.