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/MULTI_AGENT_RULES.md

@@ -151,6 +151,7 @@ To ensure that agents running in TMUX environments do not lose debug logs or pre
   - **Task Delegation**:
     - *Manual path*: Detailed task briefs may be written to a local Markdown file (e.g., `.mam/reports/brief-<job_id>.md` or a workspace path) first. The sender then issues a simple trigger command: `"Read <file_path> and execute."`
     - *Automated path*: The automated job runner (`multi-agent-mux-delegate-job submit`) automatically provisions the brief at `.mam/jobs/<job_id>/brief.md` and sends a short pointer instruction to the agent.
+    - *Sub-delegation*: an agent that delegates part of its job passes `--parent-job <its job_id>` to `submit`, so the loop waits for the sub-job and shows it to reviewers (Issue #34).
   - **Result Reporting & Feedback**:
     - *Manual/Durable reviews*: Detailed reviews, design proposals, or audit reports must be saved under `.mam/reports/<tmux_session_name>/report-<job_id>.md`.
     - *Automated job reports*: Automated execution results are saved directly to `.mam/jobs/<job_id>/<agent_name>-reports/report-final.md` (or `<clean_session_name>-reports/` for loops) as transient files.