Move shopkit/utils/money.py to shopkit/core/currency.py and rename format money - format amount everywhere…

Move shopkit/utils/money.py to shopkit/core/currency.py and rename format money - format amount everywhere…: a task in agent-harbor-tasks (Harbor dataset). Housekeeping request: money handling is core functionality, so shopkit/utils/money.py has to become shopkit/core/currency.py , and while we…

The task

Housekeeping request: money handling is core functionality, so `shopkit/utils/money.py` has to become `shopkit/core/currency.py`, and while we are at it `format_money` is renamed to `format_amount` (the other functions keep their names and behaviour).

Part of efederici/agent-harbor-tasks.