release: prepare 0.1.5 with RDNA2 kernels and in-game DLSS/FSR switching

- Add native preset K kernels for gfx1030–gfx1036 using software matrix
  products, with fast and accuracy builds and RDNA2 motion kernels.
- Follow OptiScaler's DLSS and RR preset overrides, sanitize unsupported
  values and select the preset matching the feature's quality mode.
- Enable FSR 4 under NVIDIA GPU spoofing by exposing real AMD PCI IDs
  to OptiScaler and FidelityFX modules; bundle AMD's loader and upscaler.
- Keep K on native kernels in engine auto mode unless HIP is selected,
  and fall back to CUDA for M/L when shader_float8 is unavailable.
- Add native-engine K GPU timings, preset recreation harness controls
  and regression coverage; fix the input-wait test's glibc name clash.
- Update configuration, installer guidance and release documentation,
  simplify the README and move gameplay videos to docs/videos.md.

RDNA2 kernels remain untested on RDNA2 hardware; software matrix
arithmetic was validated against WMMA on RDNA3.

config/d4r.ini.default

@@ -179,6 +179,14 @@ EngineIni =
 Cvars =
 
 [OptiScaler]
+; Switching in game from OptiScaler's menu (Insert):
+; - DLSS model: DLSS Settings > tick Render Presets Override, pick the preset (E, K, L or M), Apply Changes.
+;   Unticking it goes back to [DLSS] Model, as do presets left at DEFAULT. false always uses [DLSS] Model.
+FollowPresets = true
+; - FSR: Upscalers > Upscaler (DX12) > FSR 3.X/4. FSR 4.1 needs an RDNA3/RDNA4 GPU and GE-Proton (which provides
+;   AMD's FSR 4 library); other GPUs get FSR 3.1. true lets OptiScaler and AMD's FSR see the real GPU (the game
+;   still sees an NVIDIA one).
+Fsr4 = true
 ; OptiScaler's own FPS overlay (top left)
 FpsOverlay = true
 ; 0 = simple ... 3 = detailed with frame-time graph