New Features

- PlaceholderAPI support — DisenchantmentPlaceholderExpansion registered on startup; add PAPI as a soft-dependency
- Per-enchantment XP cost overrides — configure individual enchantment costs in repair.enchantment-costs; config migration 8 adds the new map automatically
- Configurable shatter split-count — default 1, configurable per server
- Economy GUI — in-game panel for managing disenchant/shatter economy settings ( disenchant:economy and shatter:economy commands)
- Custom locale support — locales are copied to the data folder so admins can override/translate them
- /disenchantment reload — full hot-reload: listeners re-registered, adapters re-detected, economy re-hooked
- /disenchantment debug [on|off] — runtime toggle for debug logging without a restart
- Pre/Post events — cancellable PreDisenchantEvent, PreShatterEvent, PostDisenchantEvent, PostShatterEvent for API consumers
- Custom enchantment tab-complete — third-party enchantment keys now appear in tab suggestions
- ExcellentEnchants API bump — updated to 5.4.3

Fixes

- Repair cost double-count bug in AnvilCostUtils base XP calculation
- collectEnchantments deduplication across adapters
- isPrepare=true not passed in ShatterEvent.collectEnchantments
- NMS_v1_21_R5.setItemRepairCost missing repairCost parameter
- Plugin now disables gracefully when locale resource is missing
- Enchantment states cache not invalidated on config reload
- Debug flag not synced from config on startup
- 14 additional in-code bugs resolved across two full review passes

Performance

- Config saves batched — saveConfig() deferred until commitBatch() to reduce I/O

Internal

- Replaced system-scope PAPI JAR with Maven repo dependency
- DisenchantSoundGUI + ShatterSoundGUI merged into SoundGUI
- DisenchantmentRepairGUI + ShattermentRepairGUI merged into RepairGUI
- Shared anvil event guard logic extracted into AnvilEventGuards
- AnvilFeature enum added; Config.forFeature() accessor introduced