b11064

metal : support arbitrary hc in dsv4_hc_pre (#29169)

the dsv4_hc_pre kernels hardcoded hc = 4 via a constexpr used with
simd_shuffle, so the op was rejected by supports_op for any other hc
and fell back to CPU. Kimi-K3 uses dsv4_hc_pre with hc equal to the
number of banked checkpoints in the cross-layer residual stack, which
grows with the layer index.

pass n_hc as a function constant (FC_DSV4_HC) with per-n_hc pipeline
variants, and loop over it in both pre kernels with direct loads

add test-backend-ops cases for hc = 1, 2, 3, 5, 8 and 65, gated and
not gated

Assisted-by: pi:llama.cpp/Qwen3.8-27B

Website:

• https://llama.app

Attestations:

• https://github.com/ggml-org/llama.cpp/attestations/48766233

macOS/iOS:

• macOS Apple Silicon (arm64)
• macOS Apple Silicon (arm64, KleidiAI enabled) DISABLED
• macOS Intel (x64)
• iOS XCFramework

Linux:

• Ubuntu x64 (CPU)
• Ubuntu arm64 (CPU)
• Ubuntu s390x (CPU)
• Ubuntu x64 (Vulkan)
• Ubuntu arm64 (Vulkan)
• Ubuntu x64 (CUDA 12) - CUDA 12.8 libraries
• Ubuntu x64 (CUDA 13) - CUDA 13.3 libraries
• Ubuntu arm64 (CUDA 13) - CUDA 13.3 libraries
• Ubuntu x64 (ROCm 10.0)
• Ubuntu x64 (OpenVINO)
• Ubuntu x64 (SYCL FP32)
• Ubuntu x64 (SYCL FP16)

Android:

• Android arm64 (CPU)

Windows:

• Windows x64 (CPU)
• Windows arm64 (CPU)
• Windows arm64 (OpenCL Adreno)
• Windows x64 (CUDA 12) - CUDA 12.4 DLLs
• Windows x64 (CUDA 13) - CUDA 13.4 DLLs
• Windows arm64 (CUDA 13) - CUDA 13.4 DLLs
• Windows x64 (Vulkan)
• Windows x64 (OpenVINO)
• Windows x64 (SYCL)
• Windows x64 (ROCm 10.0)

openEuler:

• DISABLED
• openEuler x86 (310p)
• openEuler x86 (910b, ACL Graph)
• openEuler aarch64 (310p)
• openEuler aarch64 (910b, ACL Graph)

• UI