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/contexts/initiative-rolls-context.tsx

@@ -0,0 +1,25 @@
+import { createContext, type ReactNode, useContext } from "react";
+import { useInitiativeRolls } from "../hooks/use-initiative-rolls.js";
+
+type InitiativeRollsContextValue = ReturnType<typeof useInitiativeRolls>;
+
+const InitiativeRollsContext =
+	createContext<InitiativeRollsContextValue | null>(null);
+
+export function InitiativeRollsProvider({ children }: { children: ReactNode }) {
+	const value = useInitiativeRolls();
+	return (
+		<InitiativeRollsContext.Provider value={value}>
+			{children}
+		</InitiativeRollsContext.Provider>
+	);
+}
+
+export function useInitiativeRollsContext(): InitiativeRollsContextValue {
+	const ctx = useContext(InitiativeRollsContext);
+	if (!ctx)
+		throw new Error(
+			"useInitiativeRollsContext requires InitiativeRollsProvider",
+		);
+	return ctx;
+}