BetterStructures-FAWE

Changed

• Async terrain scanning (P0): Moved runScanners() in NewChunkLoadEvent from synchronous runTaskLater to runTaskAsynchronously. All terrain fitness scanning (Topology.scan(), TerrainAdequacy.scan(), getBlock(), getHighestBlockAt()) now runs off the main thread, eliminating TPS impact during chunk exploration. markChunkProcessed() is dispatched back to the main thread for safe PersistentDataContainer writes.
• Thread-safe paste dispatch (P0): FitAnything.paste() now detects whether it is called from the main thread or an async thread, and automatically schedules BuildPlaceEvent and Schematic.pasteSchematic() to the main thread when needed.
• Parallel SchematicContainer initialization (P1): SchematicContainer creation (triple-nested clipboard scanning for chests, signs, spawns) now runs via parallelStream() during startup, with synchronized protection on the shared schematics multimap.
• Async config file saving (P2): New AsyncConfigSaver utility snapshots FileConfiguration via saveToString() on the calling thread, then writes to disk asynchronously. Applied to SchematicConfigField.toggleEnabled() and ModulesConfigFields.validateClones().
• Non-blocking WFC debug paste (P3): Replaced Thread.sleep(50) in WFCNode.debugPaste() with runTaskLater(1L), eliminating async thread blocking during WFC debug visualization.
• dungeonScanner dispatched to main thread: WFCGenerator constructor is not async-safe (BossBar, non-thread-safe HashSet), so dungeonScanner is now explicitly scheduled back to the main thread from the async scan pipeline.

Fixed

• dungeonScanner IndexOutOfBoundsException: Fixed pre-existing bug where ThreadLocalRandom.nextInt() used ModuleGeneratorsConfig.getModuleGenerators().size() as the upper bound instead of the filtered validatedGenerators.size(), causing potential IndexOutOfBoundsException when some generators are filtered out by world/environment checks.