engine: this GPU's own arithmetic and shared weight tiles as the builders' defaults

- layer_m.comp builds relaxed by default (M_RELAXED: f32 accumulators, paired FP8
  conversions, no activation table) with two windows per wave sharing weight tiles
  (WPW=2); M_EXACT=1 keeps NVIDIA's roundings, bit-identical to the CUDA path
- layer.comp reuses weight tiles across its waves (TPW=2 in the 32-channel layers)
- engine/rr/rr2_w.comp: one wave per window for preset F's dec0_0 and enc0, used by
  compile_rr2.py at the new default D4R_RR_RELAXED=3 (build_native_model.sh too);
  D4R_RR_FUSE=1 matches the reference's fused multiply-adds, ptx2rr.py --snorm16
- [Engine] Network defaults to vulkan; the HIP network is opt-in

packaging/d4r.ini

@@ -81,8 +81,8 @@ Enabled = false
 ; Another model K folder for games with the HDR flag (a path relative to the d4r folder, or a Windows path
 ; such as Z:\home\me\k)
 ModelDir = auto
-; auto / hip = the network on d4r's native HIP layer kernels when the model folder has them (faster),
-; vulkan = on the engine's shader
+; auto / vulkan = the network on the engine's shader, hip = on d4r's native HIP layer kernels when the model
+; folder has them
 Network = auto
 
 [Paths]