MapBox world-generation lifecycle

✅ Verified

Verified runtime entry point:

MapBox.generateNewMap() -> void

For WBML on 0.51.2, MapBox.finishMakingWorld() was the explicit completion signal that survived repeated tests. on_world_loaded was not required in the investigated generate-new-map path.

Do not use oldTile != newTile as completion. The same tiles_map, tiles_list and sample WorldTile were reused across multiple generations.

Recommended waiter: persistent coroutine host, cheap signal/live-collection polling, several stable polls, then one heavy validation pass.

Evidence: WBML-0024-fix6, WBML-0025-fix1, WBML-0030.