feat(cli,registry): introduce --herdr-workspace option and decouple socket fallback chains

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

@@ -50,6 +50,10 @@ Arguments:
                          (falls back to the registry record: agent field ->
                           session-name suffix -> pane.cmd)
   --herdr-session <name> — specify isolated herdr session name (alias: --herdr-server)
+  --herdr-workspace <name> — recorded label only; never selects a socket
+                             (use --herdr-session for that). Note: stop has no
+                             --workspace flag — the session's own workspace is
+                             read from its registry row, not from where you stand.
   --reason <reason>    — stop_reason field (default: manual_stop)
   --purge-conversation — also delete on-disk conversation artifacts;
                          status becomes terminated and resume is impossible
@@ -63,6 +67,7 @@ EOF
 SESSION_NAME=""
 AGENT=""
 HERDR_SERVER_OPT=""
+HERDR_WORKSPACE_OPT=""
 PURGE=0
 YES=0
 CAPTURE_ID=1
@@ -75,6 +80,7 @@ while [ $# -gt 0 ]; do
     --session) SESSION_NAME="$2"; shift 2 ;;
     --agent)   AGENT="$2";        shift 2 ;;
     --herdr-session|--herdr-server) HERDR_SERVER_OPT="$2"; shift 2 ;;
+    --herdr-workspace) HERDR_WORKSPACE_OPT="$2"; shift 2 ;;
     --purge-conversation) PURGE=1; shift ;;
     --yes)     YES=1; shift ;;
     --reason)  REASON="$2";       shift 2 ;;
@@ -104,7 +110,7 @@ fi
 if [ -n "$HERDR_SERVER_OPT" ]; then
   export HERDR_SESSION_NAME="$HERDR_SERVER_OPT"
 else
-  HERDR_SESSION_NAME="$(resolve_herdr_workspace "$SESSION_NAME" "${WORKSPACE:-$WORKSPACE_ROOT}")"
+  HERDR_SESSION_NAME="$(resolve_herdr_session "$SESSION_NAME" "${WORKSPACE:-$WORKSPACE_ROOT}")"
   export HERDR_SESSION_NAME
 fi