leitner 0.1.1

First release published by CI. Install with pnpm add -g leitner.

Added

• .github/workflows/publish.yml — publishes to npm on a GitHub release, using
  trusted publishing (OIDC), so no npm token exists in this repository. It
  re-runs the full check suite, refuses a tag that disagrees with
  package.json, refuses a version already on the registry, and verifies the
  built entrypoint is in the tarball before publishing.

Fixed

• The README's wrapper snippet hardcoded one machine's checkout path, so copying
  it produced a script that could not run anywhere else.
• docs/format.md presented one particular .images/ layout as "the"
  convention; the format requires nothing of the sort.

No behaviour changes — 0.1.1 is identical to 0.1.0 at runtime.