Add multi-organization support to a Next.js app (iframe embed) - TypeScript & Supabase

We have a Next.js app that runs as an iframe embed inside a parent platform, simulating a HeyGen account. Currently it handles a single HeyGen Account and Organization per session. We need to extend the initialization flow to support receiving multiple HeyGen Account's IDs at load time and letting the user pick one before the app proceeds. A technical spec and annotated codebase will be provided. Scope of work; - Extend the INIT message payload type to accept an array of organization IDs and optional display names. - Add org selection state to the existing global state provider (Zustand/Context). - Build a HeyGen Account picker modal that gates the initialization flow when multiple HeyGen accounts are present for one organization. - Ensure heygen account behavior remains fully backward-compatible. Requirements Strong React + TypeScript skills Familiar with Next.js App Router and postMessage-based iframe communication Ability to work from a written spec with minimal back-and-forth