feat(ux): B0 注入透明读端点 + F1 写作页右栏真面板

兑现「看到的=写章用的」信任牌（不变量 #6），替换写作页右栏过时假占位
（「M1 暂未接 / M2 开放」）。

后端：
- GET /projects/{id}/chapters/{no}/injection → InjectionResponse（selected
  实体 + 入选理由 + recent_n）；调既有 assemble() 回放确定性 SelectionTrace，
  无 LLM / 无 commit / 无 DDL；项目不存在→404，无大纲→selected:[]。
- 新 schemas/injection.py；tests/test_injection.py(3 测)。

前端：
- gen:api 纳入端点；纯逻辑 lib/workbench/injection.ts（理由/类型→中文徽标
  + 4 vitest）+ useInjection 读 hook。
- ChapterAssistant 改 client 组件：列出选中实体 + 理由徽标 + 空/载/错三态，
  四审段指向审稿页；Workbench 传 projectId/chapterNo。

门禁：后端 ruff/format/mypy 159/alembic 无漂移/pytest 454；
前端 lint/typecheck/vitest 167/build。

B0 可控版（PUT override pin/排除/recent_n + selection 加参 + draft 同读
override + 持久化）+ F1 可控控件待后续。

apps/api/tests/test_injection.py

@@ -0,0 +1,169 @@
+"""B0 注入透明读端点测试：GET /projects/:id/chapters/:no/injection。
+
+读取 assemble 的确定性 SelectionTrace（无 LLM、无 commit）：
+- 命中实体 + 入选理由徽标；项目不存在 → 404；无大纲 → selected: []（不报错）。
+"""
+
+from __future__ import annotations
+
+import uuid
+
+import httpx
+import pytest
+from fakes_projects import FakeProjectRepo
+from ww_api.services.credentials import STUB_OWNER_ID
+from ww_core.domain.project_repo import ProjectCreate
+from ww_core.domain.repositories import (
+    CharacterView,
+    DigestView,
+    ForeshadowView,
+    MemoryRepos,
+    OutlineView,
+    ProjectSpecView,
+    RuleView,
+    StyleView,
+    WorldEntityView,
+)
+from ww_shared import ErrorCode
+
+# ---- 内存 fake memory repos（无 DB；只够断言 SelectionTrace 形状）----
+
+
+class _OutlineRepo:
+    def __init__(self, rows: dict[int, OutlineView]) -> None:
+        self._rows = rows
+
+    async def get(self, project_id: uuid.UUID, chapter_no: int) -> OutlineView | None:
+        return self._rows.get(chapter_no)
+
+    async def list_for_project(self, project_id: uuid.UUID) -> list[OutlineView]:
+        return [self._rows[k] for k in sorted(self._rows)]
+
+
+class _CharRepo:
+    def __init__(self, rows: list[CharacterView]) -> None:
+        self._rows = rows
+
+    async def list_for_project(self, project_id: uuid.UUID) -> list[CharacterView]:
+        return list(self._rows)
+
+
+class _WorldRepo:
+    def __init__(self, rows: list[WorldEntityView]) -> None:
+        self._rows = rows
+
+    async def list_for_project(self, project_id: uuid.UUID) -> list[WorldEntityView]:
+        return list(self._rows)
+
+
+class _DigestRepo:
+    async def recent(self, project_id: uuid.UUID, k: int) -> list[DigestView]:
+        return []
+
+
+class _ForeshadowRepo:
+    async def list_for_codes(self, project_id: uuid.UUID, codes: list[str]) -> list[ForeshadowView]:
+        return []
+
+
+class _StyleRepo:
+    async def latest(self, project_id: uuid.UUID) -> StyleView | None:
+        return None
+
+
+class _RulesRepo:
+    async def all_for_project(self, project_id: uuid.UUID) -> list[RuleView]:
+        return []
+
+
+class _SpecRepo:
+    async def spec(self, project_id: uuid.UUID) -> ProjectSpecView | None:
+        return ProjectSpecView(title="测试作品", premise="测试前提")
+
+
+def _memory_repos(
+    *,
+    outline: dict[int, OutlineView] | None = None,
+    characters: list[CharacterView] | None = None,
+    world: list[WorldEntityView] | None = None,
+) -> MemoryRepos:
+    return MemoryRepos(
+        outline=_OutlineRepo(outline or {}),
+        character=_CharRepo(characters or []),
+        world_entity=_WorldRepo(world or []),
+        digest=_DigestRepo(),
+        foreshadow=_ForeshadowRepo(),
+        style=_StyleRepo(),
+        rules=_RulesRepo(),
+        project=_SpecRepo(),
+    )
+
+
+def _make_client(
+    *,
+    project_repo: FakeProjectRepo,
+    memory_repos: MemoryRepos,
+) -> httpx.AsyncClient:
+    import os
+
+    os.environ.setdefault("CREDENTIAL_ENC_KEY", "x" * 44)
+    from ww_api.main import create_app
+    from ww_api.services.project_deps import get_memory_repos, get_project_repo
+
+    app = create_app()
+    app.dependency_overrides[get_project_repo] = lambda: project_repo
+    app.dependency_overrides[get_memory_repos] = lambda: memory_repos
+    transport = httpx.ASGITransport(app=app)
+    return httpx.AsyncClient(transport=transport, base_url="http://test")
+
+
+async def _create_project(repo: FakeProjectRepo, title: str = "注入") -> uuid.UUID:
+    view = await repo.create(STUB_OWNER_ID, ProjectCreate(title=title))
+    return uuid.UUID(str(view.id))
+
+
+@pytest.mark.asyncio
+async def test_injection_lists_selected_entities_with_reasons() -> None:
+    repo = FakeProjectRepo()
+    pid = await _create_project(repo)
+    memory = _memory_repos(
+        outline={3: OutlineView(volume=1, chapter_no=3, beats={"entities": ["青檀"]})},
+        characters=[
+            CharacterView(name="林动", role="主角"),
+            CharacterView(name="青檀", role="配角"),
+            CharacterView(name="路人甲", role="龙套"),
+        ],
+    )
+    client = _make_client(project_repo=repo, memory_repos=memory)
+    async with client:
+        resp = await client.get(f"/projects/{pid}/chapters/3/injection")
+    assert resp.status_code == 200
+    body = resp.json()
+    assert body["project_id"] == str(pid)
+    assert body["chapter_no"] == 3
+    by_name = {e["name"]: e for e in body["selected"]}
+    assert "林动" in by_name and "main_character" in by_name["林动"]["reasons"]
+    assert "青檀" in by_name and "explicit_beat" in by_name["青檀"]["reasons"]
+    assert "路人甲" not in by_name  # 未命中任何理由 → 不注入
+    assert body["recent_n"] >= 1
+
+
+@pytest.mark.asyncio
+async def test_injection_unknown_project_404() -> None:
+    repo = FakeProjectRepo()
+    client = _make_client(project_repo=repo, memory_repos=_memory_repos())
+    async with client:
+        resp = await client.get(f"/projects/{uuid.uuid4()}/chapters/1/injection")
+    assert resp.status_code == 404
+    assert resp.json()["error"]["code"] == ErrorCode.NOT_FOUND
+
+
+@pytest.mark.asyncio
+async def test_injection_no_outline_returns_empty() -> None:
+    repo = FakeProjectRepo()
+    pid = await _create_project(repo)
+    client = _make_client(project_repo=repo, memory_repos=_memory_repos())
+    async with client:
+        resp = await client.get(f"/projects/{pid}/chapters/9/injection")
+    assert resp.status_code == 200
+    assert resp.json()["selected"] == []

apps/api/ww_api/routers/projects.py

@@ -26,6 +26,7 @@ from ww_core.domain.project_repo import ProjectCreate, ProjectRepo
 from ww_core.domain.repositories import MemoryRepos
 from ww_core.domain.review_repo import ReviewRepo
 from ww_core.memory import assemble
+from ww_core.memory.selection import RECENT_DIGEST_COUNT
 from ww_core.orchestrator import (
     ChapterState,
     SseEvent,
@@ -40,6 +41,7 @@ from ww_llm_gateway import Gateway
 from ww_shared import AppError, ErrorCode
 
 from ww_api.logging_config import get_logger
+from ww_api.schemas.injection import InjectionEntity, InjectionResponse
 from ww_api.schemas.projects import (
     AcceptRequest,
     AcceptResponse,
@@ -124,6 +126,38 @@ async def get_project(project_id: uuid.UUID, repo: ProjectRepoDep) -> ProjectRes
     return _to_response(view)
 
 
+@router.get("/{project_id}/chapters/{chapter_no}/injection")
+async def get_injection(
+    project_id: uuid.UUID,
+    chapter_no: int,
+    repos: MemoryReposDep,
+    project_repo: ProjectRepoDep,
+) -> InjectionResponse:
+    """本章注入透明（B0，读端点）：回放确定性 SelectionTrace。无 LLM、无 commit。
+
+    项目不存在 → 404；无大纲 → selected: []（不报错）。看到的=写章用的（不变量 #6）。
+    """
+    if await project_repo.get(STUB_OWNER_ID, project_id) is None:
+        raise AppError(ErrorCode.NOT_FOUND, f"project {project_id} not found")
+    context = await assemble(repos, project_id, chapter_no)
+    selected = [
+        InjectionEntity(kind=e.kind, name=e.name, reasons=list(e.reasons))
+        for e in context.selection.selected
+    ]
+    log.info(
+        "injection_read",
+        project_id=str(project_id),
+        chapter_no=chapter_no,
+        selected_count=len(selected),
+    )
+    return InjectionResponse(
+        project_id=project_id,
+        chapter_no=chapter_no,
+        selected=selected,
+        recent_n=RECENT_DIGEST_COUNT,
+    )
+
+
 def _encode_sse(event: SseEvent) -> str:
     """把归一事件编码为 text/event-stream 帧：`event: <name>\\ndata: <json>\\n\\n`。"""
     payload = json.dumps(event.data, ensure_ascii=False)

apps/api/ww_api/schemas/injection.py

@@ -0,0 +1,31 @@
+"""本章注入透明（B0）的响应 schema（C 扩 / ARCH §3.4、§5.3）。
+
+snake_case；前端经 OpenAPI 生成 TS 类型消费。改字段 → 前端必须 `pnpm gen:api`。
+读取无 LLM、无 commit——仅回放 assemble() 的确定性 SelectionTrace（不变量 #6）。
+"""
+
+from __future__ import annotations
+
+import uuid
+
+from pydantic import BaseModel, Field
+
+
+class InjectionEntity(BaseModel):
+    """一个被注入本章上下文的实体 + 入选理由（喂给透明面板的徽标）。"""
+
+    kind: str = Field(description="character / world_entity")
+    name: str
+    reasons: list[str] = Field(
+        default_factory=list,
+        description="explicit_beat / main_character / recent_digest / foreshadow_window",
+    )
+
+
+class InjectionResponse(BaseModel):
+    """GET /projects/:id/chapters/:no/injection：本章确定性注入留痕。"""
+
+    project_id: uuid.UUID
+    chapter_no: int
+    selected: list[InjectionEntity] = Field(default_factory=list)
+    recent_n: int = Field(description="近况摘要回看章数（确定性选择的默认参数）")

apps/web/components/workbench/ChapterAssistant.tsx

@@ -1,6 +1,29 @@
+"use client";
+
+import Link from "next/link";
+
+import {
+  kindLabel,
+  reasonLabel,
+  type InjectionEntity,
+} from "@/lib/workbench/injection";
+import { useInjection } from "@/lib/workbench/useInjection";
+
+interface ChapterAssistantProps {
+  projectId: string;
+  chapterNo: number;
+}
+
 // 右栏「本章助手」（UX §6.3）。
-// M1 无端点暴露注入选择轨迹/四审结果 → 占位说明，不编造 API。
-export function ChapterAssistant() {
+// 「本章注入（透明）」读 B0 端点，列出确定性选中的设定/角色 + 入选理由徽标——
+// 这是「看到的=写章用的」的信任牌（不变量 #6）。「四审」指向审稿页入口。
+export function ChapterAssistant({
+  projectId,
+  chapterNo,
+}: ChapterAssistantProps) {
+  const injection = useInjection(projectId, chapterNo);
+  const selected = injection.data?.selected ?? [];
+
   return (
     <aside className="hidden border-l border-line bg-panel p-4 lg:block">
       <h2 className="text-sm font-semibold text-ink">本章助手</h2>
@@ -9,19 +32,63 @@ export function ChapterAssistant() {
         <h3 className="text-xs font-semibold uppercase tracking-wide text-ink-soft">
           本章注入（透明）
         </h3>
-        <p className="mt-2 rounded border border-dashed border-line bg-bg p-3 text-xs text-ink-soft">
-          M1 暂未接：注入的设定/伏笔选择轨迹尚无对应端点，将在记忆服务接入后展示。
-        </p>
+
+        {injection.loading ? (
+          <p className="mt-2 text-xs text-ink-soft">加载注入信息…</p>
+        ) : injection.error ? (
+          <p className="mt-2 rounded border border-dashed border-line bg-bg p-3 text-xs text-ink-soft">
+            {injection.error}
+          </p>
+        ) : selected.length === 0 ? (
+          <p className="mt-2 rounded border border-dashed border-line bg-bg p-3 text-xs text-ink-soft">
+            本章暂无注入实体（先在大纲点名设定/角色）。
+          </p>
+        ) : (
+          <ul className="mt-2 space-y-2">
+            {selected.map((entity) => (
+              <EntityRow key={`${entity.kind}:${entity.name}`} entity={entity} />
+            ))}
+          </ul>
+        )}
       </section>
 
-      <section className="mt-4">
+      <section className="mt-6">
         <h3 className="text-xs font-semibold uppercase tracking-wide text-ink-soft">
           四审
         </h3>
-        <p className="mt-2 rounded border border-dashed border-line bg-bg p-3 text-xs text-ink-soft">
-          M2 开放：一致性 / 伏笔 / 文风 / 节奏。
+        <p className="mt-2 text-xs text-ink-soft">
+          一致性 / 伏笔 / 文风 / 节奏，在审稿页逐条裁决。
         </p>
+        <Link
+          href={`/projects/${projectId}/review?chapter=${chapterNo}`}
+          className="mt-2 inline-block rounded border border-cinnabar px-3 py-1.5 text-xs text-cinnabar hover:bg-[var(--color-cinnabar-wash)]"
+        >
+          去审稿 →
+        </Link>
       </section>
     </aside>
   );
 }
+
+function EntityRow({ entity }: { entity: InjectionEntity }) {
+  return (
+    <li className="rounded border border-line bg-bg p-2">
+      <div className="flex items-center gap-2">
+        <span className="rounded bg-panel px-1.5 py-0.5 text-[10px] text-ink-soft">
+          {kindLabel(entity.kind)}
+        </span>
+        <span className="text-sm text-ink">{entity.name}</span>
+      </div>
+      <div className="mt-1.5 flex flex-wrap gap-1">
+        {(entity.reasons ?? []).map((reason) => (
+          <span
+            key={reason}
+            className="rounded bg-[var(--color-cinnabar-wash)] px-1.5 py-0.5 text-[10px] text-cinnabar"
+          >
+            {reasonLabel(reason)}
+          </span>
+        ))}
+      </div>
+    </li>
+  );
+}

apps/web/components/workbench/Workbench.tsx

@@ -87,7 +87,7 @@ export function Workbench({ project, initialText = "" }: WorkbenchProps) {
           />
         </section>
 
-        <ChapterAssistant />
+        <ChapterAssistant projectId={project.id} chapterNo={chapterNo} />
       </div>
     </AppShell>
   );

apps/web/lib/api/schema.d.ts

@@ -90,6 +90,28 @@ export interface paths {
         patch?: never;
         trace?: never;
     };
+    "/projects/{project_id}/chapters/{chapter_no}/injection": {
+        parameters: {
+            query?: never;
+            header?: never;
+            path?: never;
+            cookie?: never;
+        };
+        /**
+         * Get Injection
+         * @description 本章注入透明（B0，读端点）：回放确定性 SelectionTrace。无 LLM、无 commit。
+         *
+         *     项目不存在 → 404；无大纲 → selected: []（不报错）。看到的=写章用的（不变量 #6）。
+         */
+        get: operations["get_injection_projects__project_id__chapters__chapter_no__injection_get"];
+        put?: never;
+        post?: never;
+        delete?: never;
+        options?: never;
+        head?: never;
+        patch?: never;
+        trace?: never;
+    };
     "/projects/{project_id}/chapters/{chapter_no}/draft": {
         parameters: {
             query?: never;
@@ -958,6 +980,44 @@ export interface components {
             /** Detail */
             detail?: components["schemas"]["ValidationError"][];
         };
+        /**
+         * InjectionEntity
+         * @description 一个被注入本章上下文的实体 + 入选理由（喂给透明面板的徽标）。
+         */
+        InjectionEntity: {
+            /**
+             * Kind
+             * @description character / world_entity
+             */
+            kind: string;
+            /** Name */
+            name: string;
+            /**
+             * Reasons
+             * @description explicit_beat / main_character / recent_digest / foreshadow_window
+             */
+            reasons?: string[];
+        };
+        /**
+         * InjectionResponse
+         * @description GET /projects/:id/chapters/:no/injection：本章确定性注入留痕。
+         */
+        InjectionResponse: {
+            /**
+             * Project Id
+             * Format: uuid
+             */
+            project_id: string;
+            /** Chapter No */
+            chapter_no: number;
+            /** Selected */
+            selected?: components["schemas"]["InjectionEntity"][];
+            /**
+             * Recent N
+             * @description 近况摘要回看章数（确定性选择的默认参数）
+             */
+            recent_n: number;
+        };
         /**
          * OAuthDisconnectResponse
          * @description 断开：是否删到凭据行。
@@ -1597,6 +1657,38 @@ export interface operations {
             };
         };
     };
+    get_injection_projects__project_id__chapters__chapter_no__injection_get: {
+        parameters: {
+            query?: never;
+            header?: never;
+            path: {
+                project_id: string;
+                chapter_no: number;
+            };
+            cookie?: never;
+        };
+        requestBody?: never;
+        responses: {
+            /** @description Successful Response */
+            200: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "application/json": components["schemas"]["InjectionResponse"];
+                };
+            };
+            /** @description Validation Error */
+            422: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "application/json": components["schemas"]["HTTPValidationError"];
+                };
+            };
+        };
+    };
     get_draft_projects__project_id__chapters__chapter_no__draft_get: {
         parameters: {
             query?: never;

apps/web/lib/workbench/injection.test.ts

@@ -0,0 +1,27 @@
+import { describe, expect, it } from "vitest";
+
+import { kindLabel, reasonLabel } from "./injection";
+
+describe("reasonLabel", () => {
+  it("maps each known selection reason to a Chinese badge", () => {
+    expect(reasonLabel("explicit_beat")).toBe("本章点名");
+    expect(reasonLabel("main_character")).toBe("主角常驻");
+    expect(reasonLabel("recent_digest")).toBe("近章出现");
+    expect(reasonLabel("foreshadow_window")).toBe("伏笔窗口");
+  });
+
+  it("falls back to the raw code for an unknown reason", () => {
+    expect(reasonLabel("future_reason")).toBe("future_reason");
+  });
+});
+
+describe("kindLabel", () => {
+  it("maps entity kinds to Chinese", () => {
+    expect(kindLabel("character")).toBe("角色");
+    expect(kindLabel("world_entity")).toBe("设定");
+  });
+
+  it("falls back to the raw kind when unknown", () => {
+    expect(kindLabel("mystery")).toBe("mystery");
+  });
+});

apps/web/lib/workbench/injection.ts

@@ -0,0 +1,30 @@
+// 本章注入透明（B0/F1）纯逻辑：入选理由 / 实体类型 → 中文徽标。
+// 纯函数，便于 node 环境单测；渲染层只管样式。
+
+import type { components } from "@/lib/api/schema";
+
+export type InjectionResponse = components["schemas"]["InjectionResponse"];
+export type InjectionEntity = components["schemas"]["InjectionEntity"];
+
+// SelectionReason → 作者可读徽标（对齐 ARCH §3.4 的四来源）。
+export const REASON_LABELS: Record<string, string> = {
+  explicit_beat: "本章点名",
+  main_character: "主角常驻",
+  recent_digest: "近章出现",
+  foreshadow_window: "伏笔窗口",
+};
+
+// EntityKind → 中文。
+export const KIND_LABELS: Record<string, string> = {
+  character: "角色",
+  world_entity: "设定",
+};
+
+// 未知 code 时回退原值（不吞，便于发现新理由）。
+export function reasonLabel(reason: string): string {
+  return REASON_LABELS[reason] ?? reason;
+}
+
+export function kindLabel(kind: string): string {
+  return KIND_LABELS[kind] ?? kind;
+}

apps/web/lib/workbench/useInjection.ts

@@ -0,0 +1,50 @@
+"use client";
+
+import { useEffect, useState } from "react";
+
+import { api } from "@/lib/api/client";
+import type { InjectionResponse } from "./injection";
+
+export interface UseInjection {
+  data: InjectionResponse | null;
+  loading: boolean;
+  error: string | null;
+}
+
+// 本章注入透明（B0 读端点）：挂载时拉一次确定性 SelectionTrace。
+// 只读、无 LLM、无 commit——展示「选了谁/为什么」。失败给可读文案不抛。
+export function useInjection(
+  projectId: string,
+  chapterNo: number,
+): UseInjection {
+  const [data, setData] = useState<InjectionResponse | null>(null);
+  const [loading, setLoading] = useState(true);
+  const [error, setError] = useState<string | null>(null);
+
+  useEffect(() => {
+    let cancelled = false;
+    setLoading(true);
+    setError(null);
+
+    void (async () => {
+      const { data: body, error: err } = await api.GET(
+        "/projects/{project_id}/chapters/{chapter_no}/injection",
+        { params: { path: { project_id: projectId, chapter_no: chapterNo } } },
+      );
+      if (cancelled) return;
+      if (err || !body) {
+        setError("注入信息暂不可用");
+        setData(null);
+      } else {
+        setData(body);
+      }
+      setLoading(false);
+    })();
+
+    return () => {
+      cancelled = true;
+    };
+  }, [projectId, chapterNo]);
+
+  return { data, loading, error };
+}