Chunky - Au Naturel Edit

Honestly, pretty minor changes and don't affect things much in practice, but nice to have i suppose:

Performance Optimizations

Phase 1 - Core Optimizations:

• ChunkCoordinate: Eliminated autoboxing in hashCode() and toString() methods
• Formatting.number(): Replaced synchronized static DecimalFormat with ThreadLocal to eliminate global lock contention
• Circle.isBounding(): Replaced Math.hypot() with squared distance comparison to eliminate sqrt calculation
• BukkitWorld.getDirectory(): Changed from recursive Files.walk() to direct path resolution
• EventBus: Removed redundant containsKey() before computeIfAbsent()
• RegionCache: Removed redundant containsKey() before map access

Thread-Safety Improvements:

• EventBus: Migrated from HashMap/HashSet to ConcurrentHashMap for thread-safe event handling

Concurrency Tuning:

• Hardware-aware defaults: Thread pools now scale automatically with available CPU cores
• Configurable via system properties:
  • chunky.maxWorkingCount - Maximum concurrent chunk operations
  • chunky.callbackThreads - Callback executor pool size
  • chunky.schedulerCoreThreads - Scheduler core pool size
  • chunky.schedulerMaxThreads - Scheduler max pool size
  • chunky.schedulerQueueSize - Scheduler queue capacity