llama.cpp added recurrent state rollback and took MTP speculative decoding from 123 to 183 tok/s.

Build b10731 implements rollback for qwen4exp, which MTP speculative decoding needs so the target state can move back by the number of rejected draft tokens (GitHub). Without it the context was classified for full removal and the server serialized the entire recurrent state to host memory every round, costing more than the drafting saved. On Qwen3.8-Flash-Next UD-Q4_K_XL with n-max 3 and a single slot, decoding reaches 183 tok/s on code and 144 on prose, against 123 and 83 before the change and 108 with no draft at all.