Decide which medium a newly created combatant should display in the combat tracker.
Precedence: an explicit user-set medium > the actor's current move medium > nothing (caller keeps the schema default).
An explicitly user-selected medium, if any.
The actor's current move medium, if any.
The medium to display, or null to keep the schema default.
null
Decide which medium a newly created combatant should display in the combat tracker.
Precedence: an explicit user-set medium > the actor's current move medium > nothing (caller keeps the schema default).