Maps each SoHL speaker roll-mode value to the Foundry CHAT.MODES.*
localization key for the equivalent chat-message visibility. Used to label
the roll-visibility dropdown with Foundry's own visibility strings. The
default "roll" (system) mode has no Foundry visibility equivalent, so it
keeps its own SoHL label.
Maps each SoHL speaker roll-mode value to the Foundry
CHAT.MODES.*localization key for the equivalent chat-message visibility. Used to label the roll-visibility dropdown with Foundry's own visibility strings. The default"roll"(system) mode has no Foundry visibility equivalent, so it keeps its own SoHL label.