v7.15.1

Fixed

• PORTING-MATRIX.md footnote ¹² no longer says 1password-cli has no ::gentoo atom.
  The main tree carries app-admin/op-cli-bin (2.23.0, ~amd64 ~arm64), a twin of GURU's
  app-misc/1password-cli (2.39.0, also ~arch). GURU stays the route because it is newer,
  so ¹² now names the twin and says why it is not added, and ¹³ points at ¹². No cell changes;
  dotfiles-Gentoo's package list, bootstrap and keywords are untouched (dotgibson/dotfiles-Gentoo#214).
• PORTING-MATRIX.md no longer says a privileged Gentoo bootstrap installs no gum.
  dotgibson/dotfiles-Gentoo#218 adds charm.land/gum/v2 to that path's go-install block,
  because gum has no ebuild and gentoo/mise-tools.toml covers only --user. Footnote ³⁰
  now names both providers. Footnote ³¹'s module-path table gains a gum row (six of eight
  rows now need more than the repo URL), and its "go-installed by no bootstrap.sh" line
  now names dotfiles-Gentoo. No cell changes.