BubbleSpawners

- Fix: crafted typed spawners no longer revert to a blank spawner when placed in survival without RoseStacker (or any other stacker plugin) installed. The entity type from the spawner item is now explicitly applied to the placed block on the next tick. - Add: IntegrationManager#isStackerPluginPresent() to detect whether RoseStacker, WildStacker, SilkSpawners, or SilkSpawnersV2 is active, allowing the placement fix to be skipped when a stacker plugin is handling it instead.

- Fix: prevent spawner shard exploit after ResourceWorlds/BubbleReset (/rw) world resets causing spawners to drop full spawners instead of shards. - Add: clear in-memory spawner placement fallback markers on world unload and after successful spawner breaks. - Test: add regression coverage for world reset/unload behavior and suppression of full spawner drops from other plugins.