Align conftest mock herdr and unit test assertions with Claude's simplified session-based isolation and native herdr command updates

.agents/skills/multi-agent-mux-stop/scripts/stop_session.sh

@@ -67,9 +67,21 @@ while [ $# -gt 0 ]; do
     *) echo "ERROR: unknown arg: $1" >&2; usage; exit 2 ;;
   esac
 done
+if [ -n "$AGENT" ]; then
+  case "$AGENT" in
+    claude|agy|hermes|cline) ;;
+    *) echo "ERROR: invalid agent type '$AGENT'. Allowed types are: claude, agy, hermes, cline." >&2; exit 2 ;;
+  esac
+fi
 [ -n "$SESSION_NAME" ] || { echo "ERROR: --session required" >&2; usage; exit 2; }
 [ -f "$AGENT_SESSIONS_YAML" ] || { echo "ERROR: $AGENT_SESSIONS_YAML not found" >&2; exit 1; }
 
+# Implement the purging-<session> file lock mechanism
+if [ "$PURGE" = "1" ]; then
+  touch "$WORKSPACE_ROOT/.mam/purging-$SESSION_NAME"
+  trap 'rm -f "$WORKSPACE_ROOT/.mam/purging-$SESSION_NAME"' EXIT
+fi
+
 HERDR_SERVER_NAME="$(resolve_herdr_workspace "$SESSION_NAME")"
 export HERDR_SERVER_NAME