Improve README quickstart flow

[Octane0411]

Problem

The repository README explained the TypeScript implementation in detail, but it did not give either humans or coding agents a short, reliable startup path. The action path was interrupted by roadmap content, and the documented examples omitted required runtime details such as the build step, required CLI acknowledgement flag, and Linear workflow fields.

Scope

• add a human-focused quickstart with the real startup commands
• add a collapsible agent prompt for setup and startup
• add a minimal WORKFLOW.md example with the required Linear fields
• move roadmap content below the usage and product explanation sections

Testing

• No runnable tests required; documentation-only change.