fix(issue-21): absolute brief, start-command registry, audit-log root and report paths in the delegate-job wrapper

The injected prompt, the start/success/error commands and the brief's Output
Report Path used cwd-relative `.mam/jobs/...`, and the wrapper ignored
MAM_JOBS_DIR. A creator whose cwd is a git worktree could not run them as
written, and its audit log fell back to <cwd>/.mam/delegate_job_logs.

- REGISTRY_DIR defaults to ${MAM_JOBS_DIR:-.mam/jobs} and is made absolute
  right after `cd "$WORKDIR"` (a relative value still resolves against WORKDIR)
- the publish command is shell-quoted (printf %q) and prefixed with
  DELEGATE_JOB_LOGS_DIR=<abs>, resolved by the same get_logs_dir() the
  wrapper's subscriber uses; the heartbeat timer inherits it
- direct and loop jobs share one _instructions helper; brief and report paths
  are $REGISTRY_DIR/$JOB_ID/... (absolute)
- create --onboard: absolute publish_event.py, --registry-dir and log root

Tests T1-1..T1-5 (a space in the control root, commands run from another cwd
with no workspace env).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017R3Eg7MEpSWnm1oB9ZPP6G

.agents/skills/multi-agent-mux-create/scripts/create_session.sh

@@ -503,7 +503,20 @@ if [ -n "$DELEGATE_JOB_ID" ]; then
   
   # Construct instructions matching multi-agent-mux-delegate-job format
   py_bin="$(_delegate_py_bin)"
-  pub="$py_bin .agents/skills/multi-agent-mux-delegate-job/scripts/publish_event.py --job $DELEGATE_JOB_ID"
+  # Issue #21: absolute script, registry and audit-log paths (shell-quoted), so
+  # an agent whose cwd is a git worktree can run the command as written.
+  pub_script="$WORKSPACE_ROOT/.agents/skills/multi-agent-mux-delegate-job/scripts/publish_event.py"
+  [ -f "$pub_script" ] || pub_script="$(_delegate_script publish_event.py)"
+  pub_script="$(cd -P "$(dirname "$pub_script")" && pwd -P)/$(basename "$pub_script")"
+  pub_reg="${MAM_JOBS_DIR:-${WORKSPACE_ROOT:+$WORKSPACE_ROOT/.mam/jobs}}"
+  pub_reg="${pub_reg:-.mam/jobs}"
+  mkdir -p "$pub_reg" && pub_reg="$(cd -P "$pub_reg" && pwd -P)"
+  pub_logs="$(PYTHONPATH="$SKILL_DIR:${PYTHONPATH:-}" "$py_bin" -c 'import os; from lib_py.delegation.mqtt_common import get_logs_dir; print(os.path.abspath(get_logs_dir()))' 2>/dev/null || true)"
+  pub="$(
+    if [ -n "$pub_logs" ]; then printf 'DELEGATE_JOB_LOGS_DIR=%q ' "$pub_logs"; fi
+    printf '%q ' "$py_bin" "$pub_script" --registry-dir "$pub_reg" --job "$DELEGATE_JOB_ID"
+  )"
+  pub="${pub% }"
   instructions="Your job_id is \"$DELEGATE_JOB_ID\" (the one just registered for THIS delegation).
 
 On start run:        $pub --event started.