EliteMobsEntityEnricher

Adds EliteMobs-specific fields (is_elite, is_custom_boss, is_significant_boss, and the nested elite sub-table) to Lua entity tables built by FMM's shaded Magmacore. Only invoked from LuaEntityEnricher when EliteMobs is enabled, so the direct com.magmaguy.elitemobs.* imports below only get loaded when the plugin is actually present.