Feature Request: Delete Boards, including tasks/notes

**Is your feature request related to a problem? Please describe.**
Suppose I have a Board named, ```"@Test"```
and inside that board, I have a few tasks/notes,
i.e.

```console
@Test
2. [ ] task 1
3. * note 1
6. [ ] task 2 (though do note that this is non-sequential)
```
to delete this, from my understanding, I'd need to run the command

tb -d 2 3 6

While this is fine for most boards, I just went to delete a board that had 20+ items, and as you can imagine, it was a little bit tedious making sure I didn't delete the wrong numbered item.

**Describe the solution you'd like**
Why not instead of having to type

tb -d 2 3 6

I just have to type

tb -d @Test

And remove all the items in that board (including the respective board)

This is a really cool little tool, aside from this small inconvenience, I'm really enjoying just how usable it is!

Start with the existing `tb -d` CLI command and trace how numeric item identifiers are resolved. Extend the deletion flow to accept a board name and remove its tasks, notes, and board, then verify that unrelated boards and items remain intact.

Written by the indexing model from the issue text.