fix entities.spawn in coroutines

src/logic/scripting/lua/libs/libentity.cpp

@@ -63,8 +63,10 @@ static int l_spawn(lua::State* L) {
     if (lua::gettop(L) > 2) {
         args = lua::tovalue(L, 3);
     }
-    level->entities->spawn(def, pos, std::move(args));
-    return 1;
+    entityid_t id = level->entities->spawn(def, pos, std::move(args));
+    lua::get_from(L, "entities", "get", true);
+    lua::pushinteger(L, id);
+    return lua::call_nothrow(L, 1);
 }
 
 static int l_despawn(lua::State* L) {

src/logic/scripting/scripting.cpp

@@ -549,6 +549,7 @@ void scripting::on_entity_spawn(
     const dv::value& saved
 ) {
     auto L = lua::get_main_state();
+    lua::stackguard guard(L);
     lua::requireglobal(L, STDCOMP);
     if (lua::getfield(L, "new_Entity")) {
         lua::pushinteger(L, eid);