Feature: Support for setting startup pages to open in Dual Pane

### What feature or improvement do you think would benefit Files?

If I set opening behavior to a set of pages, they cannot be set to open together as a dual pane. If I set the option to always open as dual pane, the 2 pages are each paired with the home tab and not each other!
If I set not to open as dual pane, I get two separate tabs. This is crazy behavior.

### Requirements

If I set opening behavior to a set of pages, they should open together as a dual pane.

### Files Version

4.0.24.0

### Windows Version

11 Pro

### Comments

_No response_