For Pablo — Tier 2 upgrade: Cloudflare Workers + KV (shared live state)

Currently the board saves state into the URL hash. To upgrade to a proper shared live board (one URL, auto-saves, both users see the same state in real time), the recommended approach is a Cloudflare Worker with KV storage. Estimated setup time: 30–45 mins.

Steps:
1. In the Cloudflare dashboard, create a KV namespace called CBA_BOARD.
2. Create a new Worker with the following code:

export default {
  async fetch(req, env) {
    const cors = {
      'Access-Control-Allow-Origin': '*',
      'Access-Control-Allow-Methods': 'GET, POST, OPTIONS',
      'Access-Control-Allow-Headers': 'Content-Type',
    };
    if (req.method === 'OPTIONS') return new Response(null, { headers: cors });
    const url = new URL(req.url);
    const key = 'board_state';
    if (req.method === 'POST') {
      const body = await req.text();
      await env.CBA_BOARD.put(key, body);
      return new Response('ok', { headers: cors });
    }
    const state = await env.CBA_BOARD.get(key);
    return new Response(state || '{}', {
      headers: { ...cors, 'Content-Type': 'application/json' }
    });
  }
};

3. Bind CBA_BOARD KV namespace to the Worker (in Worker settings → Variables → KV Namespace Bindings).
4. Replace the saveState() and loadState() functions in this HTML file with fetch() calls to the Worker URL.
5. Add a 30-second setInterval poll on loadState() so both users auto-refresh.

Security: Add a shared secret header check in the Worker if you don’t want the endpoint publicly writable.