CI and devshell comments say what the config does: jobTimeout bounds jobs, coverage runs nightly, dead timeout keys removed

Job-level timeout-minutes is parsed but not enforced by this runner; only
the runner's jobTimeout bounds a job. Also fixes the devshell coverage
comment, the shellcheck job comment, an option description citing a script
that is not in the repo, and comment file pointers that resolve to nothing.

nix/host-modules/swarm-victorialogs-service.nix

@@ -57,8 +57,8 @@ in
         ⚠️ Every swarm container shares the host's network namespace, so
         this is a swarm-wide claim rather than a per-container one — two
         modules picking the same number collide at runtime with no bind
-        error and nothing in any log. `state/eval-port-collisions.sh`
-        checks the class.
+        error and nothing in any log. No repo-wide
+        check catches it.
       '';
     };