Touhou Little Maid: Crimson Heart Covenant

Added covenants between players and Touhou Little Maid entities. Hold a cake and sneak-right-click a tamed Maid to become her player maid. Added hierarchical relationships with inherited inventory, task, follow, and configuration management. Maid entity tasks are now automatically synchronized with subordinate player maids. Added persistent relationships, legacy save migration, cycle detection, and configurable hierarchy depth. Fixed the client startup crash caused by the unregistered gui_maid_proxy entity. Improved native Maid GUI integration, server-side permission checks, and inventory safety during concurrent management.