b8107

mtmd: build_attn modified, flash_attn on/off via ctx_params (#19729)

macOS/iOS:

• macOS Apple Silicon (arm64)
• macOS Intel (x64)
• iOS XCFramework

Linux:

• Ubuntu x64 (CPU)
• Ubuntu x64 (Vulkan)
• Ubuntu s390x (CPU)

Windows:

• Windows x64 (CPU)
• Windows arm64 (CPU)
• Windows x64 (CUDA 12) - CUDA 12.4 DLLs
• Windows x64 (CUDA 13) - CUDA 13.1 DLLs
• Windows x64 (Vulkan)
• Windows x64 (SYCL)
• Windows x64 (HIP)

openEuler:

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