docs(issue-34): --parent-job, MAM_CHILD_WAIT_S, --wait-open-jobs, the sub-job verdict rule and the stale-review guard

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

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

@@ -46,6 +46,11 @@ multi-agent-mux-delegate-job submit \
   #   must arrive within T s of the injection or the inject fails closed.
   #   --prompt-file <path> replaces --prompt for long prompts (Issue #36): one
   #   argv string is capped at 131,072 bytes on Linux. The loop always uses it.
+  #   --parent-job <id> (Issue #34): this job is delegated from job <id>, which
+  #   must exist in the registry (else exit 1). A loop waiting on <id> waits for
+  #   it too and shows it to reviewers. Default: $MAM_JOB_ID (the remote runner
+  #   sets it), ignored with a warning when the registry lacks that job.
+  #   `registry.py list --parent <id>` lists a job's direct children.
 
 # 1b) Same, for an agent on another host (no herdr pane, no shared disk):
 #     the brief travels over the broker as a signed retained dispatch and a
@@ -165,6 +170,7 @@ Job lifecycle execution events are persistently mirrored to an append-only log u
 ## Best Practices and Pitfalls
 
 - **Subscribe-Before-Publish**: The subscriber must be running before the agent starts publishing. The `submit` command handles this automatically by launching the subscriber in the background first.
+- **Sub-delegation carries `--parent-job` (Issue #34)**: an agent that hands part of its job to another agent must pass `--parent-job <its own job_id>` (the injected instructions and `brief.md` say so). Without it the loop does not wait for the sub-job; reviewers see it only as an unattributed open job. From a git worktree the worktree's copy of this wrapper runs; the pane's `MAM_JOBS_DIR` keeps the registry the same one.
 - **Fresh job_id Propagation**: Make sure the worker agent receives the correct `JOB_ID` generated for the current run, rather than reusing stale IDs from previous sessions.
 - **Brief delivery via file path**: For long or complex prompts, write the instructions to a file (e.g. `/tmp/task-brief.md`) and pass a short prompt pointing to the file path to prevent terminal buffer overflows.
 - **Prompts injected into a live agent session MUST be English, ASCII-only, and short** — this is exactly what `--prompt`/the `instructions` string sent to `run_agent()` end up as. Any Korean (or other non-ASCII) content the task needs to convey must go in a markdown brief file (e.g. `.mam/jobs/<id>/brief.md`, written in Korean is fine) that the injected prompt merely tells the agent to read. Two independent bugs in `send_keys_safe`'s paste-verification (in `lib.sh`) made this matter in practice: (a) its marker was taken with a byte-based `tail -c 24`, which can slice a multi-byte UTF-8 (e.g. Korean) character in half; (b) the rendered pane soft-wraps long lines at the terminal width, which can split the marker across two visual lines. Both are now fixed at the source (character-safe truncation + newline-stripped matching before comparison), but keeping injected prompts short/English/file-referencing is still the cheapest way to avoid ever exercising this edge case at all — it's also simply what `submit`'s own default instruction template already does (see `Core Commands` above).