#670 CRITICAL: Branch tasks must not update parent workflow_run status

Branch tasks were updating the parent workflow_run status to 'sleeping' even after the parent task had completed. This caused orphaned workflows that would never wake up. Root cause: SUCCESS path had branch isolation check, but SLEEP path did not. Fix applied: Added 'task_name \!= BRANCH_EXECUTION_TASK' check to the SLEEP path in orchestrator.py line 671. The asymmetry was: - SUCCESS path (line 600): if task_name \!= BRANCH_EXECUTION_TASK ✓ - SLEEP path (line 665): No such check ✗ (now fixed) Impact: Workflows with parallel branches that had missing join steps would become orphaned and never complete.