fix(control-plane): derive the audit-log root from the registry in the binding and the shell defaults

from_env() fills delegate_job_logs_dir with the delegate_job_logs next to
the resolved mam_jobs_dir unless DELEGATE_JOB_LOGS_DIR is set, so a session
created with only MAM_JOBS_DIR moved no longer records the workspace's old
log root. worktree_prepare.sh passes DELEGATE_JOB_LOGS_DIR on only when the
caller set it. lib.sh and the delegate-job wrapper no longer carry a bash
copy of the default: delegate_publish_cmd, delegate_started_recorded and
_logs_dir_abs resolve it with get_logs_dir(<registry>), the wrapper fails
closed when it cannot, exports the resolved root to its children, prints
it as submit's last line, and logs takes --registry-dir.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

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

@@ -234,8 +234,10 @@ if [ -n "$CREATOR_AGENT" ]; then
   env_add=(WORKSPACE_ROOT="$MAIN"
            AGENT_SESSIONS_YAML="${AGENT_SESSIONS_YAML:-$MAIN/.mam/agent-sessions.yaml}"
            MAM_JOBS_DIR="${MAM_JOBS_DIR:-$MAIN/.mam/jobs}"
-           DELEGATE_JOB_LOGS_DIR="${DELEGATE_JOB_LOGS_DIR:-$MAIN/.mam/delegate_job_logs}"
            MAM_NO_SUBSCRIBER_DAEMON=1)
+  # Issue #57: an explicit audit-log root is passed on; otherwise create's
+  # binding derives it from MAM_JOBS_DIR (the delegate_job_logs next to it).
+  if [ -n "${DELEGATE_JOB_LOGS_DIR:-}" ]; then env_add+=(DELEGATE_JOB_LOGS_DIR="$DELEGATE_JOB_LOGS_DIR"); fi
   if [ -z "${MAM_ENV_FILE:-}" ] && [ -f "$MAIN/.mam.env" ]; then env_add+=(MAM_ENV_FILE="$MAIN/.mam.env"); fi
   rc=0
   env "${env_add[@]}" bash "$SKILL_DIR/multi-agent-mux-create/scripts/create_session.sh" "${args[@]}" || rc=$?