Rename Project to go-nuts

Renamed. 🥜 Go nuts.

What changed (11 files, all verified — builds, gofmt-clean, tests pass):

• Module path → github.com/entireio/go-nuts (go.mod, README install line)
• Package identifier → package nuts, so call sites read nuts.Connect(...), nuts.NewShutdownGroup(...)
• Log/error prefixes → "nuts: ..." throughout
• Doc & prose → package doc reads Package nuts provides...; README title and .gitignore comment read the project name go-nuts; test cert CNs → nuts-test

I kept prose/repo-name references as go-nuts and code identifiers as nuts, per your pick.

Two things I did not touch (out of scope / outward-facing — say the word and I'll help):

1. Local directory is still .../entire/entwine. Renaming it mid-session would move this shell's working directory, so I left it. You can do it later with mv ../entwine ../go-nuts.
2. The GitHub repo (entireio/entwine) — renaming that is a change on GitHub's side. Once you rename it there, GitHub auto-redirects the old path, but you'll want to update the local remote: git remote set-url origin git@github.com:entireio/go-nuts.git.

Changes are staged in the working tree but not committed — want me to commit them?

I'll branch off main (never commit the rename directly to the default branch), commit, push, and open the PR.