ci.yml calls farm.yml (now reusable) instead of the eval-only nixos-*
checks, which are gone from flake.nix. The farm job is only the
coordinator (scheduler + envoy, which now requires the farm client
cert, reachable over iroh). Each machine job joins as a builder,
evaluates its machine, builds the toplevel through the farm and leaves
when done; its outputs are in niks3 by then.

ci runs for master pushes, PRs and dispatches; a newer run for the same
ref cancels the older one, farms of different refs queue FIFO
(queue: max). update-pkgs verifies PRs with ci.yml alone.

The crit wrapper writes a fresh random 10-char id per daemon port into
/var/lib/crit-routes; a path unit turns that into an nginx map on
coaxmetal:7720 (retiolum only). neoprism proxies *.review.lassul.us there
with a wildcard cert obtained via DNS-01 (RFC2136) against a delegated
_acme-challenge.review.lassul.us zone on knot, so ids never hit CT logs.