feat: reintroduce outline navigation

apps/website/src/contexts/outline.tsx

@@ -0,0 +1,22 @@
+'use client';
+
+import { createContext, useContext, useMemo, useState } from 'react';
+import type { PropsWithChildren, Dispatch, SetStateAction } from 'react';
+import type { TableOfContentsSerialized } from '~/components/TableOfContentItems';
+
+export const OutlineContext = createContext<{
+	members: TableOfContentsSerialized[] | null | undefined;
+	setMembers: Dispatch<SetStateAction<TableOfContentsSerialized[] | null | undefined>>;
+}>({ members: undefined, setMembers: (_) => {} });
+
+export const OutlineProvider = ({ children }: PropsWithChildren) => {
+	const [members, setMembers] = useState<TableOfContentsSerialized[] | null | undefined>(undefined);
+
+	const value = useMemo(() => ({ members, setMembers }), [members]);
+
+	return <OutlineContext.Provider value={value}>{children}</OutlineContext.Provider>;
+};
+
+export function useOutline() {
+	return useContext(OutlineContext);
+}