On a Capy machine the gh viewer is `capy-ai[bot]`, not the owner (checked live
against garrytan/gbrain #6252), so "other authors" needs the PR author named:
`--author <login>` overrides the viewer; the pr-body Issue links step says to
pass it when gh runs as an app.
Files: bin/gstack-issue-links, docs/pregate.md, ship/sections/pr-body.md.tmpl,
ship/sections/pr-body.md, test/ship-issue-intent.test.ts,
test/helpers/carve-guards.ts (ship maxSizeRatio re-measured: 309,483 / 187,706 = 1.6488).
Co-authored-by: capy-ai[bot] <230910855+capy-ai[bot]@users.noreply.github.com>