fix(distribution-admin): bind site context to member and enhance shelf product filters

distribution-admin/src/MemberContext.tsx

@@ -0,0 +1,8 @@
+import { createContext, useContext } from 'react'
+import type { CurrentMember } from './api'
+
+export const MemberContext = createContext<CurrentMember | null>(null)
+
+export function useMember(): CurrentMember | null {
+  return useContext(MemberContext)
+}