One not-yet-released mob of a Streaming wave (docs/combat-feel-porting-plan.md, phase 3).
Fully precomputed at wave start by spawn_wave — power-normalized attrs, position and the
spawn id (drawn from the wave’s RNG stream in config order, so seed determinism holds no
matter when the release happens) — and converted to a SpawnEntity event on release.
Deliberately a plain essences struct (not the event): the event type lives in
overlord_event_system, which depends on this crate.
Typed, config-level mirror of overlord_event_system’s WaveFightData (the
shape prepare_fight_script builds inline and passes to ctx.spawn_wave).
Holds the wave data as typed config — pure data, no combat and no RNG. Field
optionality mirrors WaveFightData exactly.