eCash - cashtab - fees not showing

When a transaction is made in cashtab it does not show the fee before executing the transaction.

Please add the fee amount to all fee related transactions to the screen before executing a transaction. This will make the difference between accepting and denying eCash as a crypto. The wallet should show how much a transaction will cost before executing transactions.

Also, add the ability to set custom fee amounts for transactions.

Start by tracing Cashtab's transaction flow to identify where fee-related transactions are prepared and reviewed. Confirm how fees are currently calculated before execution, then define the screens and transaction types that must show the fee and accept a custom amount. Done means the fee is visible before execution and custom fee values can be set for supported transactions.

Written by the indexing model from the issue text.