EternalCombat

GH-400 Resolve EntityMountEvent registration failure on modern Paper (#400)

• Fix: Resolve EntityMountEvent registration failure on modern Paper

Newer Paper builds (e.g. 26.1.2) removed org.spigotmc.event.entity.EntityMountEvent, causing KnockbackRegionController registration to fail and region knockback protection to be disabled.

Resolve EntityMountEvent at runtime (checking Bukkit, Paper, and Spigot packages) and register it reflectively while preserving the 1.19.3 compile target for compatibility.

• Optimize dynamic mount event handling

Co-authored-by: Martin Sulikowski vluckyyy.biznes@gmail.com