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/components/roll-mode-menu.tsx

@@ -0,0 +1,88 @@
+import type { RollMode } from "@initiative/domain";
+import { ChevronsDown, ChevronsUp } from "lucide-react";
+import { useEffect, useLayoutEffect, useRef, useState } from "react";
+
+interface RollModeMenuProps {
+	readonly position: { x: number; y: number };
+	readonly onSelect: (mode: RollMode) => void;
+	readonly onClose: () => void;
+}
+
+export function RollModeMenu({
+	position,
+	onSelect,
+	onClose,
+}: RollModeMenuProps) {
+	const ref = useRef<HTMLDivElement>(null);
+	const [pos, setPos] = useState<{ top: number; left: number } | null>(null);
+
+	useLayoutEffect(() => {
+		const el = ref.current;
+		if (!el) return;
+		const rect = el.getBoundingClientRect();
+		const vw = document.documentElement.clientWidth;
+		const vh = document.documentElement.clientHeight;
+
+		let left = position.x;
+		let top = position.y;
+
+		if (left + rect.width > vw) left = vw - rect.width - 8;
+		if (left < 8) left = 8;
+		if (top + rect.height > vh) top = position.y - rect.height;
+		if (top < 8) top = 8;
+
+		setPos({ top, left });
+	}, [position.x, position.y]);
+
+	useEffect(() => {
+		function handleMouseDown(e: MouseEvent) {
+			if (ref.current && !ref.current.contains(e.target as Node)) {
+				onClose();
+			}
+		}
+		function handleKeyDown(e: KeyboardEvent) {
+			if (e.key === "Escape") onClose();
+		}
+		document.addEventListener("mousedown", handleMouseDown);
+		document.addEventListener("keydown", handleKeyDown);
+		return () => {
+			document.removeEventListener("mousedown", handleMouseDown);
+			document.removeEventListener("keydown", handleKeyDown);
+		};
+	}, [onClose]);
+
+	return (
+		<div
+			ref={ref}
+			className="card-glow fixed z-50 min-w-40 rounded-lg border border-border bg-card py-1"
+			style={
+				pos
+					? { top: pos.top, left: pos.left }
+					: { visibility: "hidden" as const }
+			}
+		>
+			<button
+				type="button"
+				className="flex w-full items-center gap-2 px-3 py-1.5 text-left text-emerald-400 text-sm hover:bg-hover-neutral-bg"
+				onClick={() => {
+					onSelect("advantage");
+					onClose();
+				}}
+			>
+				<ChevronsUp className="h-4 w-4" />
+				Advantage
+			</button>
+			<button
+				type="button"
+				className="flex w-full items-center gap-2 px-3 py-1.5 text-left text-red-400 text-sm hover:bg-hover-neutral-bg"
+				onClick={() => {
+					onSelect("disadvantage");
+					onClose();
+				}}
+			>
+				<ChevronsDown className="h-4 w-4" />
+				Disadvantage
+			</button>
+		</div>
+	);
+}