Gemma 4-E2B / Vulkan RADV native PP512/TG128

User reports Gemma-4-E2B at 109 t/s generation and 3382 t/s prompt processing on an AMD Strix Halo 128GB system with a single Radeon 8060S iGPU. Setup is llama.cpp with UD-Q4_K_XL, full offload, batch 2048 and flash attention, using the RADV Vulkan backend. The figures are separate llama-bench pp512 and tg128 microbenchmarks, not one end-to-end request; the AMDVLK backend gave 954 t/s prompt and 99 t/s generation.