Eye Tracked Foveated DLSS Support + OpenXR Lifecycle fix

This fork prerelease includes everything from v0.1.2-periphery.1
and fixes the lifetime of the OpenXR layer used for eye tracking.

Changes:

• Keep the OpenXR layer loaded while its gaze snapshot function is cached.
• Prevent calls through a stale function pointer after the OpenXR loader
  releases its reference to the layer.
• Release the retained layer reference when gaze state is reset.
• Add regression coverage for layer retention, simulated instance
  recreation, and cleanup.

Includes the previous dynamic eye-tracked foveation, DLSS-NR output,
and peripheral DLAA hot-load fixes.

Download the attached ZIP for the usable add-on.
Installation instructions and runtime requirements are in README.md.
Keep the OpenXR layer DLL and JSON manifest together.

This release is tagged from fix/retain-openxr-layer without merging
the branch into main.
CheekyFoveatedDLSSEyeTracked.zip