b9689

metal : add f16 and bf16 support for concat operator (#24724)

• metal : add f16 and bf16 support for concat operator

Extend the Metal backend concat operator to support f16 and bf16 tensor
types in addition to the existing f32 and i32 support.

• Template kernel_concat on type T with specializations for float, half,
  bfloat, and int
• Add type-specific pipeline getter ggml_metal_library_get_pipeline_concat()
• Update device support check to allow f16 unconditionally and bf16 when
  device supports bfloat16
• Update dispatch to select the correct kernel specialization by type

Assisted-by: pi:llama.cpp/Qwen3.6-27B

• metal : extend concat operator to support f16, bf16, i8, i16 and i64

Assisted-by: pi:llama.cpp/Qwen3.6-27B

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 (ROCm 7.2)
• Ubuntu x64 (OpenVINO)
• Ubuntu x64 (SYCL FP32)
• Ubuntu x64 (SYCL FP16)

Android:

• Android arm64 (CPU)

Windows:

• Windows x64 (CPU)
• Windows arm64 (CPU)
• Windows x64 (CUDA 12) - CUDA 12.4 DLLs
• Windows x64 (CUDA 13) - CUDA 13.3 DLLs
• Windows x64 (Vulkan)
• Windows x64 (OpenVINO)
• Windows x64 (SYCL)
• Windows x64 (HIP)

openEuler:

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

UI:

• UI