[Feature Request] Add option to force 100% UI rendering in WPF regardless of system DPI scaling

In modern enterprise environments, it's common to use laptops with a default display scaling of **150%**, while external monitors remain at **100%**. This mixed-DPI setup—despite having the same resolution—causes WPF applications to behave inconsistently:

- UI elements are resized unexpectedly
- Text becomes oversized or blurry
- Layouts break or overflow
- Critical functionality becomes inaccessible

This severely impacts usability, maintainability, and business productivity.

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### Request:

Please add a manifest setting or API that allows developers to **force WPF applications to render at 100% scale**, regardless of the system's DPI settings or PerMonitorV2 behavior.

#### Suggested options:

- Manifest tag:
```xml
fixed96dpi
```
- API call:
```csharp
SetProcessDpiFixed96(); // Forces 96 DPI rendering
```
- Windows setting:
“Allow apps to ignore display scaling” toggle for advanced users

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### Why this matters:

- Current DPI Awareness modes (`system`, `perMonitor`, `perMonitorV2`) do not allow full control over rendering scale
- Even with `SetProcessDpiAwareness()` or `SetProcessDPIAware()`, Windows 11 still enforces DPI scaling when dragging windows between monitors
- Developers have no reliable way to ensure consistent UI rendering across mixed-DPI environments

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### Impact:

This issue affects thousands of enterprise applications and users globally. It causes visual inconsistencies, functional errors, and user frustration—ultimately hindering productivity and contributing to economic inefficiency.

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