refactor(runtime): add run DDD boundary skeleton

backend/packages/harness/deerflow/runtime/runs/domain/identifiers.py

@@ -0,0 +1,27 @@
+"""Lightweight identifiers for the run runtime domain."""
+
+from __future__ import annotations
+
+from typing import NewType
+
+RunId = NewType("RunId", str)
+ThreadId = NewType("ThreadId", str)
+AssistantId = NewType("AssistantId", str)
+UserId = NewType("UserId", str)
+
+
+def require_non_empty(value: str, *, field_name: str) -> str:
+    """Return a stripped identifier value, rejecting empty identifiers."""
+    normalized = value.strip()
+    if not normalized:
+        raise ValueError(f"{field_name} must not be empty")
+    return normalized
+
+
+__all__ = [
+    "AssistantId",
+    "RunId",
+    "ThreadId",
+    "UserId",
+    "require_non_empty",
+]