fix(id_order): keep an orphaned marker blocking while its herdr session is alive (Issue #63)

A create/resume killed after spawning its pane but before registering its
row left a marker whose owner pid was dead; the next same-cwd waiter pruned
it on the pid alone and could start a second session that discovers the
same workspace conversation id (PR #69 review P1).

- Markers record the herdr server. A dead owner's marker is pruned only once
  its row is registered for the attempt (running, newer epoch: the row
  decides) or `_herdr has-session` reports the session gone; an unanswered
  probe counts as alive. On timeout the kill-session command is printed.
- A live marker of another process for the waiter's own session name is kept
  and blocks instead of being deleted; the waiter's own pid's markers go.
- Tests: orphan / registered / gone / same-session / missing pane pid cases,
  and a create-level reproduction against mock herdr (fails before the fix).

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

.agents/skills/lib.sh

@@ -2043,7 +2043,8 @@ mam_id_order_wait() {
   local workspace="$1" agent="$2" session_name="$3" uuid="${4:-}"
   local abs; abs="$(mam_abs_workspace "$workspace")"
   env_python "$AGENT_SESSIONS_YAML" wait --cwd "$abs" --agent "$agent" \
-    --session "$session_name" --owner-pid "$$" --uuid "$uuid" <<'PYEOF'
+    --session "$session_name" --owner-pid "$$" --uuid "$uuid" \
+    --herdr-server "${HERDR_SESSION_NAME:-}" <<'PYEOF'
 import sys
 from lib_py.agents.id_order import main
 sys.exit(main(sys.argv[1:]))