feat(frontend): 五类交互接入 AI 对话留痕 + Workbench 抽屉入口（AC-3）

- RefinePanel/ChapterRewritePanel：结束后 append [author(意见/答复), ai(产出)]；
  clarify buffer-until-concluded——澄清 Q&A（原意见→反问→答复）缓冲，随最终产出批
  一起落库同 thread；纯放弃不记。refine ai 行 meta 存 version_no+原选段（每版重锚）。
- ContinuePanel：ai-only（续写无作者输入），每候选一条 ai 气泡 meta{candidate_index}。
- GeneratorRunner：成功后 append [author(字段摘要, meta{tool_key,input_fields}),
  ai(渲染预览, meta{tool_key,output_kind})]；空产物不记。lib/toolbox/aiSummary.ts 纯助手+单测。
- InlineToolbox→GeneratorRunner 透传 append+本章号；ToolboxPage 用 silent 直投项目级(chapter_no=null)。
- Workbench：挂 useAiConversation 单实例 + AiConversationDrawer + 底栏「AI 对话」入口（flag 灰度），
  三个 DRAFT-only 再接受回调（替换整章/插入正文/回填选段），成功关抽屉+toast、漂移不盲替换。

apps/web/lib/toolbox/aiSummary.test.ts

@@ -0,0 +1,51 @@
+import { describe, expect, it } from "vitest";
+
+import type { ToolInputFieldView } from "@/lib/api/types";
+import type { PreviewModel } from "./toolbox";
+import { fieldSummary, renderPreviewText } from "./aiSummary";
+
+const fields: ToolInputFieldView[] = [
+  { name: "brief", label: "脑洞", type: "textarea", required: true, help: null },
+  { name: "count", label: "数量", type: "number", required: false, help: null },
+];
+
+describe("fieldSummary", () => {
+  it("拼出「label：value」摘要，跳过空值", () => {
+    const summary = fieldSummary(fields, { brief: "废柴逆袭", count: "" });
+    expect(summary).toBe("脑洞：废柴逆袭");
+  });
+
+  it("多字段用 · 连接", () => {
+    const summary = fieldSummary(fields, { brief: "扮猪吃虎", count: "3" });
+    expect(summary).toBe("脑洞：扮猪吃虎 · 数量：3");
+  });
+
+  it("字段为空 / 无值 → 空串", () => {
+    expect(fieldSummary([], {})).toBe("");
+    expect(fieldSummary(fields, {})).toBe("");
+  });
+});
+
+describe("renderPreviewText", () => {
+  it("把预览项渲染成人读文本（heading + 字段 + 正文）", () => {
+    const preview: PreviewModel = {
+      kind: "IdeaListResult",
+      items: [
+        {
+          heading: "废柴逆袭",
+          fields: [{ label: "钩子", value: "扮猪吃虎" }],
+          body: null,
+        },
+        { heading: null, fields: [], body: "一段开篇正文。" },
+      ],
+    };
+    const text = renderPreviewText(preview);
+    expect(text).toContain("废柴逆袭");
+    expect(text).toContain("钩子：扮猪吃虎");
+    expect(text).toContain("一段开篇正文。");
+  });
+
+  it("空预览 → 空串", () => {
+    expect(renderPreviewText({ kind: "x", items: [] })).toBe("");
+  });
+});