b10684

sycl: make --fit respect --fit-target better (#27629)

improve the --fit algorithm to take into account the actual peak
required VRAM for a given context size on a SYCL backend.

This includes both properly accounting for how much VRAM is required
when the allocated context is fully used (which makes the reported
context drop below what it did before, but stop it OOMing) as well
as preventing some overly-conservative calculations which meant too much
VRAM was being reserved.

Tested on a Arc b70 with unsloth's qwen3.8 (Q4_K_XL), able to get 262144 context,
fully usable, with q8_0 KV and MTP and 4k ubatch size using --fit-target 1

Website:

• https://llama.app

Attestations:

• https://github.com/ggml-org/llama.cpp/attestations/43863701

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 7.14)
• 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 13.3 DLLs
• Windows arm64 (CUDA 13) (preview) - CUDA 13.4 DLLs
• Windows x64 (Vulkan)
• Windows x64 (OpenVINO)
• Windows x64 (SYCL)
• Windows x64 (ROCm 7.14)

openEuler:

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

UI:

• UI