fix(mtmd): memory_can_shift() logic bug

Signed-off-by: JamePeng <jame_peng@sina.com>

Author: JamePeng

llama_cpp/llama_chat_format.py

@@ -3641,7 +3641,7 @@ def __call__(
 
                     # Stage 5: Multimodal Physical OOM Defense
                     if n_past + chunk_n_tokens > llama.n_ctx():
-                        if llama._ctx.memory_can_shift():
+                        if not llama._ctx.memory_can_shift():
                             raise RuntimeError(
                                 f"{self.log_prefix}(__call__): Context Shift is explicitly disabled by the C++ backend "
                                 f"(n_pos_per_embd > 1 or incompatible M-RoPE). "