Support complex numbers in PowerToys Run

### Description of the new feature / enhancement

From https://github.com/microsoft/PowerToys/pull/47506#issuecomment-4675342517
> The latest versions of the underlying Mages engine do support complex numbers, but I believe our front-end parser and results interpreter currently do not, which is why the error message is displayed.
>
>Please feel free to request this under a separate issue.

### Scenario when this would be used?

I want to do calculations with complex numbers and be able to show results containing complex numbers

### Supporting information

_No response_

Start with the PowerToys Run calculator entry point and trace how its front-end parser and results interpreter interact with the Mages engine. Check the existing handling of calculation expressions and displayed results, then verify that complex-number calculations and returned complex values work without the current error.

Written by the indexing model from the issue text.