Add advantage/disadvantage rolling for initiative

Right-click or long-press the d20 button (per-combatant or Roll All)
to open a context menu with Advantage and Disadvantage options.
Normal left-click behavior is unchanged.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/domain/src/index.ts

@@ -84,7 +84,11 @@ export {
 	removeCombatant,
 } from "./remove-combatant.js";
 export { retreatTurn } from "./retreat-turn.js";
-export { rollInitiative } from "./roll-initiative.js";
+export {
+	type RollMode,
+	rollInitiative,
+	selectRoll,
+} from "./roll-initiative.js";
 export { type SetAcSuccess, setAc } from "./set-ac.js";
 export { type SetHpSuccess, setHp } from "./set-hp.js";
 export {