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>

apps/web/src/App.tsx

@@ -7,6 +7,7 @@ import {
 	type Creature,
 	type CreatureId,
 	isDomainError,
+	type RollMode,
 } from "@initiative/domain";
 import {
 	useCallback,
@@ -147,12 +148,15 @@ export function App() {
 	);
 
 	const handleRollInitiative = useCallback(
-		(id: CombatantId) => {
+		(id: CombatantId, mode: RollMode = "normal") => {
+			const diceRolls: [number, ...number[]] =
+				mode === "normal" ? [rollDice()] : [rollDice(), rollDice()];
 			const result = rollInitiativeUseCase(
 				makeStore(),
 				id,
-				rollDice(),
+				diceRolls,
 				getCreature,
+				mode,
 			);
 			if (isDomainError(result)) {
 				setRollSingleSkipped(true);
@@ -165,12 +169,20 @@ export function App() {
 		[makeStore, getCreature, encounter.combatants, sidePanel.showCreature],
 	);
 
-	const handleRollAllInitiative = useCallback(() => {
-		const result = rollAllInitiativeUseCase(makeStore(), rollDice, getCreature);
-		if (!isDomainError(result) && result.skippedNoSource > 0) {
-			setRollSkippedCount(result.skippedNoSource);
-		}
-	}, [makeStore, getCreature]);
+	const handleRollAllInitiative = useCallback(
+		(mode: RollMode = "normal") => {
+			const result = rollAllInitiativeUseCase(
+				makeStore(),
+				rollDice,
+				getCreature,
+				mode,
+			);
+			if (!isDomainError(result) && result.skippedNoSource > 0) {
+				setRollSkippedCount(result.skippedNoSource);
+			}
+		},
+		[makeStore, getCreature],
+	);
 
 	const handleViewStatBlock = useCallback(
 		(result: SearchResult) => {