Add Fabric 1.20.4 support based on 0.5.0

[babou1537]

Summary

This PR adds Fabric support for Minecraft 1.20.4 based on the 0.5.0 Fabric version.
If you prefer, I can retarget this PR to a dedicated branch created from the 0.5.0 tag.

Main changes:

• Update Minecraft, Yarn, Fabric Loader and Fabric API versions for 1.20.4.
• Update WorldEdit dependencies to 7.3.0 for Minecraft 1.20.4.
• Replace the removed CustomPayloadS2CPacket usage with ServerPlayNetworking.send(...).
• Keep the same curvebuilding:bezier-pos packet identifier and preserve the existing packet serialization format.
• Update the client receiver to use the shared packet identifier.

Tested with

• Minecraft 1.20.4
• Fabric Loader 0.17.2
• Fabric API 0.97.0+1.20.4
• WorldEdit 7.3.0
• Java 17

Build command:

.\gradlew.bat clean build

Result :

BUILD SUCCESSFUL

Notes

This is intended as a minimal compatibility port for Fabric 1.20.4. No gameplay behavior was intentionally changed.