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/lib_py/delegation/wrapper.py

@@ -5,12 +5,16 @@ injects; everything it used to decide in bash is here, and it branches only on
 what a subcommand prints or returns:
 
   sub-status <rc> --job J --registry-dir R   subscriber rc -> job status (was _map_sub_rc)
-  subscriber-up <rc>                         exit 0: a subscriber that ended before
+  subscriber-up <rc> [--print]               exit 0: a subscriber that ended before
                                              SUBSCRIBED still lets the job proceed
   exit-code <status>                         the wrapper's exit code (was _rc_for, with
                                              MAM_DELEGATE_FAIL_CLOSED=0 -> 0)
   wait-rc <rc>                               `wait`'s rc (either clock is a timeout, 2)
-  stall-watch <session> <agent>              exit 0: start the stall watcher (Issue #30)
+  stall-watch <session> <agent> [--print]    exit 0: start the stall watcher (Issue #30)
+
+The two yes/no decisions answer by exit code (0 yes, 1 no); with --print they
+print `yes`/`no` and exit 0, so a failure to decide (any other exit code, or
+no answer) cannot pass for "no". The wrapper uses --print.
   finalize-begin / finalize-end ...          finalize_unfinished, split around the one
                                              herdr diagnostic probe bash still runs
 
@@ -294,12 +298,15 @@ def _parser() -> argparse.ArgumentParser:
     s.add_argument("rc", type=int)
     s.add_argument("--job", required=True)
     s.add_argument("--registry-dir", required=True)
-    sub.add_parser("subscriber-up").add_argument("rc", type=int)
+    s = sub.add_parser("subscriber-up")
+    s.add_argument("rc", type=int)
+    s.add_argument("--print", action="store_true", help="print yes/no and exit 0")
     sub.add_parser("exit-code").add_argument("status")
     sub.add_parser("wait-rc").add_argument("rc", type=int)
     s = sub.add_parser("stall-watch")
     s.add_argument("session")
     s.add_argument("agent")
+    s.add_argument("--print", action="store_true", help="print yes/no and exit 0")
     for name in ("finalize-begin", "finalize-end"):
         s = sub.add_parser(name)
         s.add_argument("--job", required=True)
@@ -325,18 +332,25 @@ def _parser() -> argparse.ArgumentParser:
     return p
 
 
+def _yes_no(answer: bool, printed: bool) -> int:
+    if printed:
+        print("yes" if answer else "no")
+        return 0
+    return 0 if answer else 1
+
+
 def main(argv: Optional[List[str]] = None) -> int:
     a = _parser().parse_args(argv)
     if a.cmd == "sub-status":
         print(sub_status(a.rc, a.registry_dir, a.job))
     elif a.cmd == "subscriber-up":
-        return 0 if subscriber_up(a.rc) else 1
+        return _yes_no(subscriber_up(a.rc), a.print)
     elif a.cmd == "exit-code":
         print(exit_code(a.status))
     elif a.cmd == "wait-rc":
         print(wait_rc(a.rc))
     elif a.cmd == "stall-watch":
-        return 0 if stall_watch(a.session, a.agent) else 1
+        return _yes_no(stall_watch(a.session, a.agent), a.print)
     elif a.cmd == "finalize-begin":
         print(finalize_begin(a))
     else: