Donut Orders

New Features

• Added Shulker Box delivery support — matching items inside shulkers count toward order fulfillment.
• Shulker contents are scanned from shulkers placed in the delivery GUI and from shulkers anywhere in the seller's inventory.
• Added items.yml for configuring allowed order materials separately from config.yml.
• Added Modrinth update check on plugin startup (update-check.enabled in config.yml).
• Added donutorders as a command alias for /orders.

Improvements

• Allowed materials are validated server-side when creating orders (prevents GUI bypass).
• Invalid material names in items.yml log warnings instead of crashing the plugin.
• /orders admin reload now reloads config.yml, messages.yml, and items.yml.