#1248 SYCL build fails on Intel Arc A770 (Alchemist) - v0.1.40.1

Description

Building the SYCL engine on CachyOS with an Intel Arc A770 (Alchemist) fails with multiple errors.

**Environment:**
- OS: CachyOS (Arch-based)
- Kernel: 7.2.6-1-cachyos
- GPU: Intel Arc A770 (DG2/Alchemist)
- Driver: xe (Kernel driver in use: xe)
- oneAPI DPC++/C++ Compiler: 2026.1.1
- Strata version: v0.1.40.1 (commit 82f46a8)

**Build command:**
`cmake -S sycl -B build-sycl -G Ninja -DCMAKE_C_COMPILER=icx -DCMAKE_CXX_COMPILER=icpx -DSTRATA_SYCL_PARITY=OFF`
`cmake --build build-sycl --target strata`

**Errors (from build log):**

1. **`fused_gr.dp.cpp`:**
   `/home/javal/Strata/sycl/src/kernels/cuda/fused_gr.dp.cpp:1607:6: error: functions that differ only in their return type cannot be overloaded`
   (definition is `void`, header declares `bool`)

2. **`expert_source.cpp`:**
   `/home/javal/Strata/sycl/src/core/expert_source.cpp:2938:14: error: call to 'load_experts_gguf' is ambiguous`
   (two conflicting definitions)

**Full build log:** (attach /tmp/strata_build_v0140.log)

The Alchemist (A770) architecture is not listed as tested in `docs/INTEL_ARC.md`. It seems the SYCL port has compilation issues that are specific to this architecture.