Refactor App.tsx from god component to context-based architecture

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

apps/web/src/hooks/use-action-bar-animation.ts

@@ -0,0 +1,38 @@
+import { useLayoutEffect, useRef, useState } from "react";
+
+export function useActionBarAnimation(combatantCount: number) {
+	const wasEmptyRef = useRef(combatantCount === 0);
+	const [settling, setSettling] = useState(false);
+	const [rising, setRising] = useState(false);
+	const [topBarExiting, setTopBarExiting] = useState(false);
+
+	useLayoutEffect(() => {
+		const nowEmpty = combatantCount === 0;
+		if (wasEmptyRef.current && !nowEmpty) {
+			setSettling(true);
+		} else if (!wasEmptyRef.current && nowEmpty) {
+			setRising(true);
+			setTopBarExiting(true);
+		}
+		wasEmptyRef.current = nowEmpty;
+	}, [combatantCount]);
+
+	const empty = combatantCount === 0;
+	const risingClass = rising ? "animate-rise-to-center" : "";
+	const settlingClass = settling ? "animate-settle-to-bottom" : "";
+	const exitingClass = topBarExiting
+		? "absolute inset-x-0 top-0 z-10 px-4 animate-slide-up-out"
+		: "";
+	const topBarClass = settling ? "animate-slide-down-in" : exitingClass;
+	const showTopBar = !empty || topBarExiting;
+
+	return {
+		risingClass,
+		settlingClass,
+		topBarClass,
+		showTopBar,
+		onSettleEnd: () => setSettling(false),
+		onRiseEnd: () => setRising(false),
+		onTopBarExitEnd: () => setTopBarExiting(false),
+	};
+}