feat(scope): implement workspace-scoped session isolation (A-1) and native Herdr session naming (A-5)

.agents/skills/multi-agent-mux-resume/scripts/resume_session.sh

@@ -44,8 +44,8 @@ if [ -z "$UUID" ]; then
   exit 1
 fi
 
-HERDR_SERVER_NAME="$(resolve_herdr_workspace "$SESSION_NAME")"
-export HERDR_SERVER_NAME
+HERDR_SESSION_NAME="$(resolve_herdr_session "$SESSION_NAME")"
+export HERDR_SESSION_NAME
 
 # 2. If herdr is alive, print warning or attach.
 if herdr has-session -t "$SESSION_NAME" 2>/dev/null; then