Windows terminal command line should allow for a `--zoom` modifier when starting a new tab/window

### Description of the new feature

I have my desktop environment fully bootstrapped automatically via pwsh and `wt` CLI. However the one glaring gap is:
- I can't specify the zoom level on each pane individually (and `--size` has no impact on this)

Each pane has a different purpose and need different levels of scaling against the default. I would also be okay with a absolute rather than relative flag like: `--font-size 12px`

### Example Terminal Window 1

Start by tracing existing wt command-line parsing, especially --size, and the code that applies pane font scaling. Clarify whether the requested option is relative or absolute, then verify that a new tab or window can assign the requested scaling independently to each pane.

Written by the indexing model from the issue text.