[Bank] Add event dispatch on account events

### What component of Red (cog, command, API) would you like to see improvements on?

Bank's API

### Describe the enhancement you're suggesting.

It would be nice if cogs can take advantage of listeners for the Bank cog.
Cogs could know when an user's account get changed, pruned, spend money, and so on...

### Anything else?

_No response_

Start by reading the Bank API and the existing cog listener patterns. Define which account events need dispatch, including account changes, pruning, and spending, then verify that cogs can receive them consistently. Done means the Bank API dispatches the agreed events for those account operations and listener behavior is covered by tests.

Written by the indexing model from the issue text.