The Ctrlable Hardware Manager Proxy add-on now ships from the shared Ctrlable add-on repository, so adding one URL gets you every Ctrlable add-on rather than one per product.
Add this in Settings → Add-ons → Add-on Store → ⋮ → Repositories:
https://github.com/Ctrlable/ha-addon
Then install Ctrlable Hardware Manager Proxy.
repository.yaml has been removed from this repo deliberately: without it Home
Assistant will not treat this as an add-on source, so nobody can end up installing
a copy that drifts from the one in ha-addon.