Launching the new ChatPilot documentation site

Today we replaced the placeholder docs app with a Docusaurus site designed for real operator and developer workflows.

What is included in the first production pass:

• onboarding and local development setup
• architecture documentation for the API, worker, and event flow
• FastAPI endpoint and webhook reference
• guide-driven content for campaigns, automations, and payments
• deployment guidance for static hosting and containerized services

Next additions will focus on versioned API changes, richer platform screenshots, and deeper SDK examples once the external integration surface stabilizes.