Allow Fixing of Row/Col number, resize window only changes font size.

### Description of the new feature

Allow setting the number of rows and columns to fixed numbers.
If the user then adjusts the size of the window, font size is adjusted instead of adding more rows or columns.

### Proposed technical implementation details

_No response_

The issue names no files, tests, or entry points. Start by locating the Windows Terminal implementation for window resizing, row and column calculation, and font-size adjustment; done means users can set fixed row and column counts and resizing changes font size instead of adding rows or columns.

Written by the indexing model from the issue text.