ec-node: moq-rs draft-07 for Cloudflare relay

nix/modules/ec-node.nix

@@ -294,7 +294,14 @@ in
                   ${lib.optionalString cfg.tlsDisableVerify "cmd+=(--tls-disable-verify)"}
                   ${extraArgsLine}
 
-                  exec "''${cmd[@]}"
+                  # Keep the unit alive even if the relay is temporarily unreachable.
+                  # This avoids `switch-to-configuration test` failing due to a unit that exits
+                  # quickly during activation.
+                  trap 'exit 0' INT TERM
+                  while true; do
+                    "''${cmd[@]}" || true
+                    sleep 2
+                  done
                 '';
             };
           in