feat(backend): AI 反问澄清预检端点——refine 侧结构化 clarify（WFW-9 M1，路线A 两阶段）

润色「再沟通」意见含糊时先反问给选项（路线A：问题走独立非流式 JSON 预检端点，正文仍走
既有 refine 一字不改）。新增：
- ClarifyDecision/ClarifyQuestion/ClarifyOption 结构化 schema（既有 output-schema 处，供
  producer 与端点共用）；clarify_refine.md 教条（含糊→need_clarification+≤1问+2–4锚定选项+
  自由输入；明确→verification 放行；防循环）；注册 clarify_refine_spec(analyst 档,#24)+
  SCHEMA_CATALOG + 重生成金标准。
- clarify_node：build_clarify_request 纯函数(缓存前缀不含易变) + run_clarify（gateway.run
  结构化，判别/校验失败确定性回退 need_clarification=false，只读不写库）。
- POST /projects/{id}/chapters/{no}/refine/clarify → ClarifyDecision（analyst 网关，404/503，
  末尾 commit 记账）。**既有 refine 端点/RefineRequest/Response 完全未改**。
门禁绿：ruff/mypy 227/pytest 900(+test_clarify_spec/_node/style clarify)/alembic 无漂移。

packages/core/tests/test_clarify_node.py

@@ -0,0 +1,127 @@
+"""WFW-9 M1 clarify 节点单测：build_clarify_request + run_clarify（路线A 两阶段）。
+
+注入 mock 网关（产 `ClarifyDecision` parsed），无真 LLM、无真 Postgres。clarify 是独立
+非流式预检（不在写章/审稿流水线），裸函数；只判不改、**不写库**（不变量 #3）。asyncio_mode=auto。
+"""
+
+from __future__ import annotations
+
+import uuid
+
+from fakes_orchestrator import FakeRunGateway
+from ww_agents import (
+    ClarifyDecision,
+    ClarifyOption,
+    ClarifyQuestion,
+    WorldGenResult,
+    clarify_refine_spec,
+)
+from ww_core.orchestrator import build_clarify_request, run_clarify
+
+PROJECT = uuid.UUID("00000000-0000-0000-0000-000000000001")
+USER = uuid.UUID("00000000-0000-0000-0000-0000000000aa")
+
+_NEED = ClarifyDecision(
+    need_clarification=True,
+    questions=[
+        ClarifyQuestion(
+            question="你想让这段更有张力，是指哪种方向？",
+            options=[
+                ClarifyOption(label="加快节奏", value="拆短句、压缩铺陈"),
+                ClarifyOption(label="加重冲突", value="强化人物对立"),
+            ],
+            allow_free_text=True,
+        )
+    ],
+)
+
+_CLEAR = ClarifyDecision(
+    need_clarification=False,
+    verification="我会把被字句改成主动句，其余不动，对吗？",
+)
+
+
+# ---- build_clarify_request：analyst 档 + 结构化 + 缓存前缀无易变 ----
+
+
+def test_build_clarify_request_declares_analyst_tier_and_schema() -> None:
+    req = build_clarify_request(
+        clarify_refine_spec,
+        context="## 待重写段落\n原段。\n\n## 改写指令\n再改改",
+        user_id=USER,
+        project_id=PROJECT,
+    )
+    # 不变量 #2：只声明 analyst 档，不传 model。
+    assert req.tier == "analyst"
+    # 结构化预检：非流式 + 带 ClarifyDecision output_schema。
+    assert req.stream is False
+    assert req.output_schema is ClarifyDecision
+    # 注入材料进 input（断点后）。
+    assert "再改改" in req.input
+
+
+def test_build_clarify_request_system_prefix_is_doctrine_only_cacheable() -> None:
+    # 不变量 #9：system 前缀只放教条、cache=True，无历史/时间戳/UUID（可缓存）。
+    req = build_clarify_request(
+        clarify_refine_spec, context="ctx", user_id=USER, project_id=PROJECT
+    )
+    assert len(req.system) == 1
+    block = req.system[0]
+    assert block.cache is True
+    assert block.text == clarify_refine_spec.system_prompt
+    # 易变值绝不进缓存前缀。
+    assert str(PROJECT) not in block.text
+    assert "ctx" not in block.text
+
+
+# ---- run_clarify：正常返回 + 校验失败确定性回退 ----
+
+
+async def test_run_clarify_returns_need_clarification_decision() -> None:
+    gateway = FakeRunGateway(_NEED)
+
+    result = await run_clarify(
+        clarify_refine_spec,
+        context="## 待重写段落\n原段。",
+        gateway=gateway,
+        user_id=USER,
+        project_id=PROJECT,
+    )
+
+    assert isinstance(result, ClarifyDecision)
+    assert result.need_clarification is True
+    assert len(result.questions) == 1
+    assert result.questions[0].options[0].label == "加快节奏"
+    assert gateway.call_count == 1
+
+
+async def test_run_clarify_returns_clear_decision() -> None:
+    gateway = FakeRunGateway(_CLEAR)
+
+    result = await run_clarify(
+        clarify_refine_spec,
+        context="ctx",
+        gateway=gateway,
+        user_id=USER,
+        project_id=PROJECT,
+    )
+
+    assert result.need_clarification is False
+    assert result.verification is not None
+
+
+async def test_run_clarify_falls_back_to_no_clarification_on_wrong_parsed() -> None:
+    # 判别/校验失败：网关返回非 ClarifyDecision（畸形/降级）→ 确定性回退不问、放行。
+    gateway = FakeRunGateway(WorldGenResult(entities=[]))
+
+    result = await run_clarify(
+        clarify_refine_spec,
+        context="ctx",
+        gateway=gateway,
+        user_id=USER,
+        project_id=PROJECT,
+    )
+
+    assert isinstance(result, ClarifyDecision)
+    assert result.need_clarification is False
+    assert result.questions == []