Set up a repo's agent instructions

Set up, or reorganize, a repository's agent instructions. Makes AGENTS.md the one instructions file (what the project is, its commands, workflow, conventions, and rules), with a CLAUDE.md that imports it, project skills in .agents/skills behind a .claude/skills symlink, a git-ignored CLAUDE.local.md for machine-specific notes, and a decision log. Optionally adds a GitHub Issues roadmap (labels and filing rules) and a release system (release-please with Conventional Commits, or hand-cut releases through the relay workflow). Use when a repo has no AGENTS.md or its instructions are scattered, and whenever the user asks to "set up instructions", "write an AGENTS.md", "set up …