#715 BUG: python_task.py swallows AbsurdSleepError in sandbox fallback path

In engine/tools/python_task.py lines 373-376, the except Exception block catches AbsurdSleepError when sandbox execution raises it. Problem: - In non-strict mode: AbsurdSleepError is swallowed, workflow falls back to direct execution instead of sleeping - In strict mode: AbsurdSleepError is wrapped in RuntimeError, losing its semantics Fix: Add explicit handler for AbsurdSleepError BEFORE the Exception handler to re-raise it.