feat(packages): add ds4 package with ROCm/Strix Halo backend

Add antirez/ds4 — DeepSeek V4 Flash/PRO local inference engine built
with the ROCm strix-halo target for AMD Radeon 8060S (gfx1151).
Wires up all 8 ROCm transitive dependencies (clr, hipblas, hipblas-common,
hipblaslt, hipcub, rocblas, rocprim, rocwmma) via explicit include/lib paths.

packages/ds4/default.nix

@@ -0,0 +1,2 @@
+{ pkgs, ... }:
+pkgs.callPackage ./package.nix { }