The five pages moved from docs/ into website/docs/developer-guide were
never added to sidebars.ts, so the site did not link them, and they kept
repo-relative links (../tests/..., ../scripts/..., ../website/docs/...)
that only resolved from the old docs/ location. Register them under a
Packaging & Releases category and point the repo-file links at GitHub;
package-management.md now links the moved completion note in place.