Smarter hunting aim, safer bot persistence and the last of the old blue theme gone.

Added

• Persistence autosave - every bot's tasks (with aim point), inventory, XP and settings are saved every 2 minutes, so a crash loses at most that much. Config: persistence.autosave-interval-seconds (default 120, 0 = off, minimum 30).
• Inventory / XP database backup - bot inventories and XP are also written to the plugin database (fpp_bot_inventories) and recovered on restart if they are missing from bot-data.yml.

Changed

• Hitbox aiming (hunting / PVE) - bots aim at any exposed part of a mob's hitbox (feet, head, corners) instead of locking onto its center, so they hit mobs in farms that only show their feet. Target scanning uses the same check.
• No aiming at hidden mobs - a mob with no visible part of its hitbox is never aimed at or attacked. Chasing bots walk to a better angle; standing bots drop it and look for another target.
• Head look-back off while tasking - bots no longer turn their head to look at players while hunting, running a click task or walking.
• Purple theme - leftover blue GUI panes (inventory label, Pathfinding and Perf categories) are now purple.