性能优化，修复编译bug

src/ai_scheduler.cpp

@@ -135,7 +135,7 @@ ModelHandle AiScheduler::LoadModel(const std::string& model_path, std::string& e
         // If we create multiple contexts, bind them to different NPU cores when possible.
         // This reduces contention and avoids the single-context serialization bottleneck.
         {
-            int mask = RKNN_NPU_CORE_0_1_2;
+            rknn_core_mask mask = RKNN_NPU_CORE_0_1_2;
 #if defined(RKNN_NPU_CORE_0) && defined(RKNN_NPU_CORE_1) && defined(RKNN_NPU_CORE_2)
             if (pool_size >= 3) {
                 const int idx = i % 3;