Postiz Agent + Upgrade nodejs version

Introducing the new Postiz agent and MCP.
You can schedule posts or multiple posts to multiple social channel from the chat.
This require ChatGPT.

Upgraded to node 22:

• Support for ESM imports from commonjs
• Better version less bug
• Changed encryption to support node 22.

What's Changed

• Postiz Agent by @nevo-david in #1027
  Full Changelog: v2.7.0...v2.8.0