add dialogue and cutscene system

src/ScriptEngine.cpp

@@ -47,6 +47,23 @@ void ScriptEngine::init(Game* game) {
             npcs[index]->setTarget(Eigen::Vector3f(x, y, z), std::move(cb));
         });
 
+    api.set_function("start_dialogue",
+        [game](const std::string& dialogueId) {
+            if (!game->requestDialogueStart(dialogueId)) {
+				std::cerr << "[script] start_dialogue failed for id: " << dialogueId << "\n";
+            }
+        });
+
+    api.set_function("set_dialogue_flag",
+        [game](const std::string& flag, int value) {
+            game->setDialogueFlag(flag, value);
+        });
+
+    api.set_function("get_dialogue_flag", 
+        [game](const std::string& flag) {
+            return game->getDialogueFlag(flag);
+        });
+
     runScript("resources/start.lua");
 }