Function register_precombat_buffs 

pub(crate) fn register_precombat_buffs(
    built: &mut BuiltCombatSystem,
    data: &ResolvedGameData,
    specs: &[PrecombatBuffSpec],
) -> Result<(), EngineError>

Register every spec in specs onto built, then the data-selected food buff; idempotent per spell id.

Errors

Returns an engine construction error when a selected buff cannot be resolved or registered.