Function apply_replacements 

pub fn apply_replacements(
    game: &mut GameState,
    event: &mut ReplacementEvent,
) -> ReplacementResult

Apply all applicable replacement effects to a game event.

Free function wrapper — auto-selects first effect (no agent prompt). Used by callers that don’t have access to agents (e.g. action.rs).

Mirrors Java ReplacementHandler.run(ReplacementType, Map<AbilityKey,Object>).