1.21.x Update

This update brings full compatibility with Minecraft 1.21.x.

What's New

• Updated to Minecraft 1.21.1 (compatible with 1.21 and above)
• Updated to Fabric API 0.110.0+1.21.1
• Now requires Java 21

Technical Changes

• Completely rewrote the networking system to use Fabric's new typed CustomPayload packet API
• Migrated item settings from FabricItemSettings to vanilla Item.Settings
• Updated food component API to 1.21 format
• Fixed screen rendering to be compatible with 1.21 UI changes
• Fixed Identifier usage to use Identifier.of() factory method

Bug Fixes

• Fixed quiz screen not displaying when using a Study Card
• Fixed config screen text rendering behind background blur
• Fixed statistics view getting stuck on "Loading statistics..."
• Fixed scroll behavior in statistics view

as requested by MattiaAbate GitHub Issue #1