feat: upscaling using drs system

[doodlum]

Summary by CodeRabbit

• New Features

  • Unified Upscaling system with selectable methods (TAA/FSR/XeSS/DLSS), frame‑generation support, new depth/refraction and underwater upscaling passes, and integrated UI/settings.

• Improvements

  • Dynamic sampling for screen‑space shadows and runtime‑configurable light clustering.
  • Better VR per‑eye handling, refined dynamic resolution, jitter, depth handling, and performance overlay frame‑generation diagnostics.

• Removed

  • Legacy standalone upscaler integrations replaced by the unified Upscaling feature.

• Chores

  • Added DirectX headers and XeSS port, updated dependencies, gitignore and submodule cleanup; license/metadata updates.