Extract Engine Task

Problem

A Rails team needs help with a task in this area:

Use when extracting existing Rails app code into a reusable engine — must extract incrementally over big-bang, preserve existing behavior first and verify regression coverage passes before proceeding (do not extract and change behavior in the same step), ensure each slice has one coherent responsibility, minimal new public API, passing regression tests, and a clear next step.

The team has asked for a concise implementation artifact that a reviewer can inspect without needing to observe the agent's process.

Output

Create answer.md with:

• a short plan for the work
• the concrete Rails-oriented artifact or recommendation
• the verification steps or quality gates that should be run
• any assumptions that affect the result