MAINT: Consider allcontributors

[HaoZeke]

https://github.com/all-contributors/all-contributors

but also
https://github.com/orgs/the-turing-way/discussions/4245

and the metatensor ecosystem uses

https://contrib.rocks

which seems more straightforward..

[HaoZeke]

Closing as optional meta: all-contributors is not blocking engineering work; can be revisited in a release chore PR without an open issue.

[HaoZeke]

Reopened: closed in triage by mistake; keep open per maintainer direction (2026-06-27).