refactor(runtime): add run DDD boundary skeleton

backend/packages/harness/deerflow/runtime/runs/execution/supervisor.py

@@ -0,0 +1,18 @@
+"""Run execution supervision contract."""
+
+from __future__ import annotations
+
+from typing import Protocol
+
+from ..domain import CancelAction, RunId
+
+
+class RunSupervisor(Protocol):
+    """Controls lifecycle operations for already scheduled runs."""
+
+    async def cancel(self, run_id: RunId, *, action: CancelAction = CancelAction.interrupt) -> bool: ...
+
+
+__all__ = [
+    "RunSupervisor",
+]