re-promote

Project reboot skill: archive the old repo (rename to -deprecated_NNN, make private), create a fresh repo with the same name, migrate with clean squash history, scan and remove files that shouldn't be public (secrets, internal docs, binaries), transfer open issues, verify and push, then promote to public after user approval. Use this skill when the user wants to reboot, restart, re-launch, re-promote, or clean-slate a repository. Also supports extracting features from the current session into a standalone project, and promoting private repos to public with readiness checks.