Support Wide Layout in Presentation Mode

This extension is great for quick, one-off presentations, but I miss one important feature: wide layout.

I use 16:9 display and a lot of area is wasted on the left an right side.

This area could be useful, consider this example: create slide header bullet, nest a new portal under it (`Ctrl`+`Shift`+`Enter`), then create multi-column layout inside this portal (`/c2`) and you get something like this:

After `/start presentation`:

After increasing zoom (`Ctrl`+`+`)

As you can see, not ideal.

**Suggested behavior:** if a bullet has Presentation Powerup applied, and is a document with wide layout set, respect this setting in presentation mode.

Start at the presentation mode entry point and trace how a bullet with Presentation Powerup is rendered, comparing the document's wide-layout setting with the current presentation sizing. Verify the example with nested portals and `/c2`, and consider the work done when wide-layout presentations use the available 16:9 space without requiring extra zoom.

Written by the indexing model from the issue text.