Prepare Papercuts for public release

[0xmrwn]

What

• publish Papercuts as a source-only npm CLI with a strict nine-file package allowlist
• add isolated global-install and bunx artifact verification
• add pinned Linux/macOS CI and tag-driven npm/GitHub release automation
• add the MIT license, contribution boundary, and public README
• credit Steve Ruiz for the original papercuts idea
• remove low-value ADRs from the public tree

Release contract

• package version remains manually selected
• the tag must match package.json and point to main
• macOS and Linux checks pass before publication
• npm publication uses GitHub OIDC trusted publishing after the one-time package bootstrap
• the exact npm tarball is attached to the GitHub release; no binaries are published

Checks

• bun run check - 22 tests plus compiled-binary, global package, and bunx smoke
• bun audit - no vulnerabilities
• exact npm 11.18.0 tarball installation
• actionlint
• git diff --check