fix(issue-17): a failed yes/no decision is not a "no" (review codex R1)

subscriber-up and stall-watch answered only by exit code, so a call that
could not run (module error rc 1, missing interpreter 127) read as "no":
with a subscriber that had ended 0, the error path mapped 0 to completed
and the submit ended with 0; a failed stall-watch silently skipped the
watcher.

Both now take --print: the answer is printed as yes/no and the exit code
is 0 for either. The wrapper asks with --print through _decided_yes, so a
nonzero exit, no answer or anything else is _decision_failed (ERROR line,
exit 1). Without --print the rc contract is unchanged (yes 0, no 1).

Tests: subscriber-up (direct and loop/discuss call sites) and stall-watch,
each failing by traceback, rc 127 or no answer with a subscriber that
ended 0, end the submit with 1 and the ERROR line - at 8241bd5 eight of the
nine ended with 0 (the loop/no-answer one ended with 1 through the loop's
own result and failed only on the ERROR line); yes and no keep their
branches in both paths; --print unit table; the static guard forbids an
rc-read yes/no decision.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HCGpJXhSZasJLU38ksDghe

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

@@ -118,6 +118,18 @@ _decided() {
   printf -v "$__var" '%s' "$__out"
 }
 
+# _decided_yes <subcommand> <args...>: a yes/no decision (asked with --print,
+# so "no" is an answer and a failed call is not): returns 0 for yes, 1 for no.
+_decided_yes() {
+  local yn
+  _decided yn "$@" --print
+  case "$yn" in
+    yes) return 0 ;;
+    no) return 1 ;;
+  esac
+  _decision_failed "$1" "answer '$yn'"
+}
+
 # _exit_for <status>: exit with the wrapper exit code for a job status.
 _exit_for() {
   local code
@@ -381,7 +393,7 @@ EOF
       else
         local sub_exit=0
         wait "$sub_pid" 2>/dev/null || sub_exit=$?
-        if _decide subscriber-up "$sub_exit"; then
+        if _decided_yes subscriber-up "$sub_exit"; then
           sub_ready=1
           break
         else
@@ -553,7 +565,7 @@ EOF
         else
           local sub_exit=0
           wait "$sub_pid" 2>/dev/null || sub_exit=$?
-          if _decide subscriber-up "$sub_exit"; then
+          if _decided_yes subscriber-up "$sub_exit"; then
             sub_ready=1
             break
           else
@@ -715,7 +727,7 @@ reap_subscriber() {
 start_stall_watch() {
   local session="$1" agent="$2" tok="${3:-}" att="${4:-}"
   STALL_PID=""
-  _decide stall-watch "$session" "$agent" || return 0
+  _decided_yes stall-watch "$session" "$agent" || return 0
   local args=(--job "$JOB_ID" --registry-dir "$REGISTRY_DIR" --target "${session#herdr:}"
               --agent "$agent" --herdr-session "${HERDR_SESSION_NAME:-}" --watch-pid "$$")
   [ -n "$tok" ] && args+=(--expect-dispatch-token "$tok")