refactor(chain): 链 runner 经公开 aget_state.interrupts 判暂停——弃私有 __interrupt__ 键（CR-M3）

apps/api/ww_api/services/chain_runner.py

@@ -161,13 +161,13 @@ def _chain_result(state: dict[str, Any], *, awaiting_chapter: int | None) -> dic
     }
 
 
-def _extract_awaiting_chapter(final: dict[str, Any]) -> int | None:
-    """从图返回值判 interrupt：有 `__interrupt__` → 取暂停章号；否则 None（跑完）。
+def _extract_awaiting_chapter(interrupts: Sequence[Any]) -> int | None:
+    """从 pending interrupts 判暂停章号：空 → None（跑完）；否则取首个 interrupt 载荷的章号。
 
-    interrupt 载荷 = `{"chapter_no": n}`（见链图 `_accept` 节点）。LangGraph 把它放在
-    `final["__interrupt__"]`（Interrupt 对象列表）。容错读 `.value`/dict 两种形。
+    interrupts 经**公开** `graph.aget_state(config).interrupts`（`StateSnapshot`）拿到，不再
+    反手 ainvoke 返回值里的私有 `__interrupt__` 键。载荷 = `{"chapter_no": n}`（见链图 `_accept`
+    节点）。容错读 `.value`/dict 两种形。
     """
-    interrupts = final.get("__interrupt__")
     if not interrupts:
         return None
     first = interrupts[0]
@@ -244,9 +244,11 @@ async def run_chain_job(
                 resume_value = [d.model_dump() for d in resume_decisions]
                 raw_final = await graph.ainvoke(Command(resume=resume_value), config=config)
 
-            final: dict[str, Any] = dict(raw_final)
-            awaiting_chapter = _extract_awaiting_chapter(final)
-            result = _chain_result(final, awaiting_chapter=awaiting_chapter)
+            # 经公开 `StateSnapshot.interrupts` 判 pending interrupt（不反手私有 `__interrupt__`）；
+            # checkpointer 仍在 `checkpointer_ctx()` 上下文内，aget_state 可读同一 thread 检查点。
+            snapshot = await graph.aget_state(config)
+            awaiting_chapter = _extract_awaiting_chapter(snapshot.interrupts)
+            result = _chain_result(dict(raw_final), awaiting_chapter=awaiting_chapter)
             await _finish(session_factory, job_id, result, awaiting=awaiting_chapter is not None)
         log.info(
             "chain_job_settled",