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,