ChallengeUtil

Adds two new challenge systems and integrates them across startup, reset and UI:

• New listeners: TimedRandomItemListener (gives progressive random loot every 30s) and BlockBreakRandomizerListener (replaces block drops with deterministic/randomized items per match).
• Registered listeners and exposed getters in ChallengeUtil; StartCommand now starts the timed challenge and ResetCommand stops it. FullReset now resets the block-break randomizer state.
• FullResetCommand.performHolodeckReset made public; world deletion now unloads Overworld, Nether and End (with a short delay) to avoid file-lock issues on Windows and then deletes/regenerates worlds asynchronously.
• DataManager: added reloadData() and expanded clearAllData() to clear timer/world/teamrace/speedrun milestones, save and reload to ensure on-disk state matches memory after resets.
• Settings GUI and SettingsGUIListener updated to expose new challenge toggles (timed_random_item, block_break_randomizer) and added language entries for messages; config.yml added settings for block_break_randomizer and an optional fullreset-on-startup toggle.
• Version bumped to 1.4.0.

These changes implement two new RNG-based challenges, ensure proper lifecycle handling during start/reset/fullreset, and fix world-unload race conditions during regeneration.