fix: harden deployment checks

setup.sh

@@ -148,6 +148,12 @@ ensure_couch_user() {
 
 remove_group_membership() {
   local group_name="$1"
+  if ! id -u "${COUCH_USER}" >/dev/null 2>&1; then
+    if [[ "${MODE}" == "check" ]]; then
+      record_check SKIP "${COUCH_USER} group check for ${group_name}: user missing"
+    fi
+    return 0
+  fi
   if ! getent group "${group_name}" >/dev/null 2>&1; then
     return 0
   fi