Detect OrderLines stuck in render_status='processing' for >30min,
revoke their Celery task, mark failed, update render_job_doc, and
emit a single CHANNEL_ALERT batch notification to admins.
Runs every 5min via beat schedule alongside recover_stuck_cad_files.
Section B (tenant_id in JWT) confirmed already complete from Phase 4.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Hartmut
69e94e25e3