Update README

Update the project README.md with comprehensive documentation.

1. Analyze Project Structure and State

   • List the files in the root directory to identify the project type (Node.js, Python, etc.).
   • Read key configuration files if they exist (e.g., package.json, tsconfig.json, shopify.app.toml, fly.toml, requirements.txt, Gemfile, cargo.toml).
   • List the contents of valid source directories (e.g., app/, src/, lib/, components/) to understand the architecture.

2. Read Existing Documentation

   • Read the current README.md to preserve any manual sections or specific instructions the user has added.
   • If available, read .agent/brain/task.md or implementation_plan.md to understand recent changes and current features (optional, do not fail if missing).