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/application/src/roll-initiative-use-case.ts

@@ -6,7 +6,9 @@ import {
 	type DomainError,
 	type DomainEvent,
 	isDomainError,
+	type RollMode,
 	rollInitiative,
+	selectRoll,
 	setInitiative,
 } from "@initiative/domain";
 import type { EncounterStore } from "./ports.js";
@@ -14,8 +16,9 @@ import type { EncounterStore } from "./ports.js";
 export function rollInitiativeUseCase(
 	store: EncounterStore,
 	combatantId: CombatantId,
-	diceRoll: number,
+	diceRolls: readonly [number, ...number[]],
 	getCreature: (id: CreatureId) => Creature | undefined,
+	mode: RollMode = "normal",
 ): DomainEvent[] | DomainError {
 	const encounter = store.get();
 	const combatant = encounter.combatants.find((c) => c.id === combatantId);
@@ -50,7 +53,11 @@ export function rollInitiativeUseCase(
 		cr: creature.cr,
 		initiativeProficiency: creature.initiativeProficiency,
 	});
-	const value = rollInitiative(diceRoll, modifier);
+	const effectiveRoll =
+		mode === "normal"
+			? diceRolls[0]
+			: selectRoll(diceRolls[0], diceRolls[1] ?? diceRolls[0], mode);
+	const value = rollInitiative(effectiveRoll, modifier);
 
 	if (isDomainError(value)) {
 		return value;