新增根据帧数控制可见性

client/core/eval/ProjectEvaluator.h

@@ -0,0 +1,31 @@
+#pragma once
+
+#include "domain/Project.h"
+
+#include <QHash>
+#include <QPointF>
+#include <QString>
+#include <QVector>
+
+namespace core::eval {
+
+struct ResolvedEntity {
+    core::Project::Entity entity;  // 拷贝：originWorld/imageTopLeftWorld 已替换为求值后的值
+    double opacity = 1.0;          // 0..1
+};
+
+struct ResolvedTool {
+    core::Project::Tool tool;      // 拷贝：originWorld 已替换为求值后的值
+    double opacity = 1.0;          // 0..1
+};
+
+struct ResolvedProjectFrame {
+    QVector<ResolvedEntity> entities;
+    QVector<ResolvedTool> tools;
+};
+
+/// 逐帧求值：处理父子跟随与工具可见性淡入淡出。
+ResolvedProjectFrame evaluateAtFrame(const core::Project& project, int frame, int fadeFrames = 10);
+
+}  // namespace core::eval
+