repo-rails clarified repeatable project setup

repo-rails exists because repeatedly hand-assembling the same issue, branch, PR, and review conventions is a poor way to begin every new project. Recent work there has stayed focused on that central setup problem rather than broadening into a much larger framework.

The more recent simplification passes kept the GitHub workflow structure, preserved repo-owned instructions such as AGENTS.md, and reduced some of the extra ceremony around target scaffolding. That is a healthier shape for a system that is supposed to make future projects easier to start.