fix(attach): hints print the row's attach_command (Issue #72, comments 926/930, U1)

create's closing hint, the delegate-job wrapper's dispatch hint and stop's
stuck-TUI message printed the pre-#71 forms (`herdr session attach <name>`,
`HERDR_SESSION_NAME=... herdr agent attach <name>`), which miss an agent whose
name is over 32 characters or has upper case. They now print the session row's
attach_command, or lib_py.agents.sanitize.attach_command(server, name) when
there is no row (lib.sh session_attach_command). deploy/INSTALL.md and
install_mam.sh show the `herdr --session <server> agent attach <herdr name>`
form.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.agents/skills/lib.sh

@@ -1671,6 +1671,22 @@ print(resolved)
 "
 }
 
+# session_attach_command <session_name> [server]
+#
+# Issue #72: the attach hint a script prints - the session row's
+# attach_command, else the one lib_py.agents.sanitize.attach_command builds for
+# <server> (default: `default`).
+session_attach_command() {
+  MAM_STATE_JSON="$(load_state_json)" SESSION_NAME="$1" ATTACH_SERVER="${2:-default}" python3 -c "
+import os, json
+from lib_py.agents.sanitize import attach_command
+name = os.environ['SESSION_NAME']
+d = json.loads(os.environ.get('MAM_STATE_JSON') or '{}')
+row = next((s for s in d.get('herdr_sessions', []) if s.get('name') == name), {})
+print(row.get('attach_command') or attach_command(os.environ['ATTACH_SERVER'], name))
+"
+}
+
 # resolve_herdr_session <session_name> [workspace]
 #
 # returns the isolated herdr *session* name (socket/daemon) to use for this MAM session row,

.agents/skills/multi-agent-mux-create/scripts/create_session.sh

@@ -767,6 +767,6 @@ fi
 trap - EXIT
 echo "agent-sessions.yaml updated"
 echo
-echo "Attach:  herdr session attach $SESSION_NAME"
+echo "Attach:  $(session_attach_command "$SESSION_NAME" "${HERDR_SESSION_NAME:-default}")"
 echo "Delete:  use multi-agent-mux-stop skill"
 echo "Resume:  use multi-agent-mux-resume skill (after first message creates a session id)"

.agents/skills/multi-agent-mux-delegate-job/multi-agent-mux-delegate-job

@@ -1018,7 +1018,7 @@ inject_agent() {
     return 1
   fi
 
-  echo "작업이 세션 '$sess'에 전송되었습니다. (연결하려면: HERDR_SESSION_NAME=$HERDR_SESSION_NAME herdr agent attach $sess — lib.sh를 source한 셸에서 실행)"
+  echo "작업이 세션 '$sess'에 전송되었습니다. (연결하려면: $(session_attach_command "$sess" "${HERDR_SESSION_NAME:-default}"))"
   trap - EXIT
   return 0
 }

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

@@ -332,7 +332,7 @@ if [ "$PURGE" = "1" ] && [ "$HERDR_ALIVE" = "1" ]; then
   if herdr has-session -t "$SESSION_NAME" 2>/dev/null; then
     echo "ERROR: session '$SESSION_NAME' is still alive after the kill chain." >&2
     echo "  Refusing registry removal — records preserved (no state was modified)." >&2
-    echo "  Diagnose the stuck TUI (herdr session attach '$SESSION_NAME'), then re-run" >&2
+    echo "  Diagnose the stuck TUI ($(session_attach_command "$SESSION_NAME" "${HERDR_SESSION_NAME:-default}")), then re-run" >&2
     echo "  stop_session.sh --purge-conversation --yes (retry is safe/idempotent)." >&2
     delegate_publish_event "$DELEGATE_JOB_ID" cancelled "purge aborted: session still alive; no state was modified" "$DELEGATE_JOB_TOKEN" "$DELEGATE_JOB_ATTEMPT"
     exit 4