Saved world on create

- /iris create saves a new world before spawn preparation
- A crash before the first autosave keeps the world's seed

core/src/main/java/art/arcane/iris/world/IrisCreator.java

@@ -333,6 +333,8 @@ public class IrisCreator {
                         .thenCompose(Function.identity())
                         .get(WORLD_CREATE_TIMEOUT_SECONDS, TimeUnit.SECONDS);
                 if (!studio && !benchmark) {
+                    World createdWorld = world;
+                    J.sfut(() -> createdWorld.save()).get(WORLD_CREATE_TIMEOUT_SECONDS, TimeUnit.SECONDS);
                     awaitInitialSpawnPreparation(access, name);
                 }
             } catch (Throwable e) {