feat(frontend): 编辑器内「润色 / 再沟通」——选段回炉 + 追加意见迭代出版本栈，接受回填

Phase 1（写作工作台重构）：编辑器选中一段即可「润色选段」，复用同步 /refine 回炉
（只读、不写库，守不变量 #3）；不满意可「再沟通」——以上一版产出为输入 + 作者新意见
再改一版，形成版本栈（useRefine，已单测）。接受回填按内容重锚落回草稿，原文已变则
提示重选、绝不盲替换（applyRefinement，已单测）。Editor 上报选区，结果以内联卡片展示。

apps/web/components/workbench/Editor.tsx

@@ -4,17 +4,37 @@ import { useEffect, useRef } from "react";
 
 import { cn, focusRing, proseBody } from "@/lib/ui/variants";
 
+export interface EditorSelection {
+  start: number;
+  end: number;
+  text: string;
+}
+
 interface EditorProps {
   value: string;
   onChange: (value: string) => void;
   streaming: boolean;
+  // 选区变化上报（供「润色选段」等选区级 AI 动作取材）。空选区也会上报（start===end）。
+  onSelectionChange?: (selection: EditorSelection) => void;
 }
 
 // 中栏正文编辑器：宋体、720px 居中、行高 1.9（UX §2.3 / §6.3）。
 // 流式中显示朱砂光标提示（prefers-reduced-motion 下不闪烁，见 globals.css）。
-export function Editor({ value, onChange, streaming }: EditorProps) {
+export function Editor({
+  value,
+  onChange,
+  streaming,
+  onSelectionChange,
+}: EditorProps) {
   const ref = useRef<HTMLTextAreaElement>(null);
 
+  const reportSelection = (el: HTMLTextAreaElement): void => {
+    if (!onSelectionChange) return;
+    const start = el.selectionStart;
+    const end = el.selectionEnd;
+    onSelectionChange({ start, end, text: value.slice(start, end) });
+  };
+
   // 自适应高度：textarea 高度=内容高度（overflow-hidden 不内部滚动），由外层写作区
   // 单一滚动条统管。修复正文出现嵌套滚动条 + 定高 60vh 不铺满展示区的怪象。
   // min-h-[60vh] 仍作空稿时的最小可写高度（内容更长时按内容增高、外层滚动）。
@@ -35,6 +55,7 @@ export function Editor({ value, onChange, streaming }: EditorProps) {
         id="chapter-editor"
         value={value}
         onChange={(e) => onChange(e.target.value)}
+        onSelect={(e) => reportSelection(e.currentTarget)}
         readOnly={streaming}
         aria-busy={streaming}
         placeholder="夜色如墨……点击「写本章」让 AI 起草，或直接在此书写。"

apps/web/components/workbench/RefinePanel.tsx

@@ -0,0 +1,133 @@
+"use client";
+
+import { useEffect, useRef, useState } from "react";
+import { Check, MessageSquarePlus, RotateCcw, X } from "lucide-react";
+
+import { ThinkingIndicator } from "@/components/ThinkingIndicator";
+import { Button } from "@/components/ui/Button";
+import { SectionHeader } from "@/components/ui/SectionHeader";
+import { StatusNote } from "@/components/ui/StatusNote";
+import { TextArea } from "@/components/ui/TextArea";
+import { useRefine } from "@/lib/workbench/useRefine";
+
+interface RefinePanelProps {
+  projectId: string;
+  chapterNo: number;
+  // 选中原文；打开即对其回炉一次。
+  original: string;
+  // 接受回填：把选段替换为该产出（调用方按内容重锚落回草稿）。
+  onAccept: (refined: string) => void;
+  onClose: () => void;
+}
+
+// 润色 / 再沟通结果卡（内联，非模态）：打开即润色选段；作者可「再沟通」追加意见迭代出新版，
+// 择版接受回填正文，或放弃。原文只读、生成不写库（不变量 #3），accept 才动草稿。
+export function RefinePanel({
+  projectId,
+  chapterNo,
+  original,
+  onAccept,
+  onClose,
+}: RefinePanelProps) {
+  const { status, versions, latest, refine, recommunicate } = useRefine();
+  const [instruction, setInstruction] = useState("");
+  const ranRef = useRef(false);
+
+  // 打开即对选段回炉一次（仅一次，避免重复请求）。
+  useEffect(() => {
+    if (ranRef.current) return;
+    ranRef.current = true;
+    void refine(projectId, chapterNo, original);
+  }, [projectId, chapterNo, original, refine]);
+
+  const busy = status === "refining";
+
+  const onRecommunicate = (): void => {
+    const trimmed = instruction.trim();
+    if (!trimmed || busy) return;
+    setInstruction("");
+    void recommunicate(projectId, chapterNo, trimmed);
+  };
+
+  return (
+    <div className="border-b border-line bg-panel px-4 py-3 sm:px-6">
+      <div className="flex items-center justify-between gap-3">
+        <SectionHeader
+          title="润色 / 再沟通"
+          description="对选中段回炉；不满意可追加意见让 AI 再改一版，满意后接受回填。"
+        />
+        <Button onClick={onClose} variant="ghost" size="icon" aria-label="关闭润色">
+          <X className="h-4 w-4" aria-hidden="true" />
+        </Button>
+      </div>
+
+      <div className="mt-3 grid gap-3 sm:grid-cols-2">
+        <figure className="rounded border border-line bg-bg p-3">
+          <figcaption className="mb-1 text-2xs text-ink-soft">原文</figcaption>
+          <p className="whitespace-pre-wrap text-sm text-ink-soft">{original}</p>
+        </figure>
+        <figure className="rounded border border-cinnabar/40 bg-bg p-3">
+          <figcaption className="mb-1 flex items-center gap-2 text-2xs text-ink-soft">
+            改写
+            {versions.length > 0 ? (
+              <span className="rounded bg-panel px-1.5 py-0.5 tabular-nums">
+                第 {versions.length} 版
+              </span>
+            ) : null}
+          </figcaption>
+          {busy && !latest ? (
+            <ThinkingIndicator label="润色中" className="text-xs text-cinnabar" />
+          ) : latest ? (
+            <p className="whitespace-pre-wrap text-sm text-ink">{latest.refined}</p>
+          ) : status === "error" ? (
+            <StatusNote variant="danger" className="text-xs" title="回炉失败">
+              <button
+                type="button"
+                onClick={() => void refine(projectId, chapterNo, original)}
+                className="mt-1 inline-flex items-center gap-1 text-cinnabar hover:underline"
+              >
+                <RotateCcw className="h-3.5 w-3.5" aria-hidden="true" />
+                重试
+              </button>
+            </StatusNote>
+          ) : null}
+        </figure>
+      </div>
+
+      <div className="mt-3 space-y-2">
+        <label className="block">
+          <span className="sr-only">再沟通意见</span>
+          <TextArea
+            value={instruction}
+            onChange={(e) => setInstruction(e.target.value)}
+            rows={2}
+            placeholder="再沟通：想怎么改？（如「再收紧节奏」「保留这句比喻」）"
+          />
+        </label>
+        <div className="flex flex-wrap items-center gap-2">
+          <Button
+            onClick={onRecommunicate}
+            disabled={busy || instruction.trim().length === 0}
+            variant="secondary"
+            size="sm"
+          >
+            <MessageSquarePlus className="h-4 w-4" aria-hidden="true" />
+            再改一版
+          </Button>
+          <Button
+            onClick={() => latest && onAccept(latest.refined)}
+            disabled={busy || !latest}
+            variant="primary"
+            size="sm"
+          >
+            <Check className="h-4 w-4" aria-hidden="true" />
+            接受回填
+          </Button>
+          {busy ? (
+            <ThinkingIndicator label="生成中" className="text-xs text-cinnabar" />
+          ) : null}
+        </div>
+      </div>
+    </div>
+  );
+}

apps/web/components/workbench/Workbench.tsx

@@ -12,11 +12,13 @@ import {
   PanelRight,
   PenLine,
   Square,
+  Wand2,
 } from "lucide-react";
 
 import { AppShell } from "@/components/AppShell";
 import { Drawer } from "@/components/Drawer";
 import { ThinkingIndicator } from "@/components/ThinkingIndicator";
+import { useToast } from "@/components/Toast";
 import { Button } from "@/components/ui/Button";
 import { SectionHeader } from "@/components/ui/SectionHeader";
 import { StatusNote } from "@/components/ui/StatusNote";
@@ -30,10 +32,12 @@ import {
   type ChapterEntry,
 } from "@/lib/workbench/chapter";
 import { composeDirective, STYLE_PRESETS } from "@/lib/workbench/directive";
+import { applyRefinement } from "@/lib/workbench/refineApply";
 import { buttonClass } from "@/lib/ui/variants";
 import { ChapterList, ChapterListContent } from "./ChapterList";
 import { ChapterAssistant, AssistantContent } from "./ChapterAssistant";
-import { Editor } from "./Editor";
+import { Editor, type EditorSelection } from "./Editor";
+import { RefinePanel } from "./RefinePanel";
 
 interface WorkbenchProps {
   project: ProjectResponse;
@@ -64,9 +68,14 @@ export function Workbench({
   // 本章指令（T4-b）：自由文本 + 风格预设 → 写本章时组装传入 draft 生成。
   const [directive, setDirective] = useState("");
   const [presetIds, setPresetIds] = useState<string[]>([]);
+  // 选区级 AI 动作（润色/再沟通）：编辑器上报的最新选区 + 结果卡开合。
+  const [selection, setSelection] = useState<EditorSelection | null>(null);
+  const [refineOpen, setRefineOpen] = useState(false);
+  const toast = useToast();
   const autosave = useAutosave(project.id, chapterNo, initialText);
   const stream = useDraftStream();
   const lastStreamText = useRef("");
+  const canRefine = selection !== null && selection.text.trim().length > 0;
   const chapterTriggerRef = useRef<HTMLButtonElement>(null);
   const assistantTriggerRef = useRef<HTMLButtonElement>(null);
 
@@ -104,6 +113,24 @@ export function Workbench({
     autosave.onChange(value);
   };
 
+  // 接受润色/再沟通产出：按内容重锚把选段替换为产出并落草稿；原文已变则提示重选（不盲替换）。
+  const onAcceptRefine = (refined: string): void => {
+    if (selection) {
+      const next = applyRefinement(text, selection.text, refined, {
+        start: selection.start,
+        end: selection.end,
+      });
+      if (next === null) {
+        toast("正文已改动，找不到原选段，请重新选择后再润色。", "error");
+      } else {
+        setText(next);
+        autosave.onChange(next);
+      }
+    }
+    setRefineOpen(false);
+    setSelection(null);
+  };
+
   // 字数统计非空白字符（与中文读者直觉一致：标点/空格不计入正文体量）。
   const wordCount = text.replace(/\s+/g, "").length;
   const closePanel = (): void => setMobilePanel(null);
@@ -153,11 +180,21 @@ export function Workbench({
             presetIds={presetIds}
             onTogglePreset={togglePreset}
           />
+          {refineOpen && canRefine && selection ? (
+            <RefinePanel
+              projectId={project.id}
+              chapterNo={chapterNo}
+              original={selection.text}
+              onAccept={onAcceptRefine}
+              onClose={() => setRefineOpen(false)}
+            />
+          ) : null}
           <div className="flex-1 overflow-auto px-6 py-8">
             <Editor
               value={text}
               onChange={onEditorChange}
               streaming={stream.isStreaming}
+              onSelectionChange={setSelection}
             />
           </div>
           <Toolbar
@@ -171,6 +208,8 @@ export function Workbench({
             liveMessage={liveMessage}
             onWrite={onWrite}
             onStop={stream.stop}
+            canRefine={canRefine}
+            onRefineSelection={() => setRefineOpen(true)}
           />
         </section>
 
@@ -358,6 +397,9 @@ interface ToolbarProps {
   liveMessage: string;
   onWrite: () => void;
   onStop: () => void;
+  // 选区级润色：有非空选区时可用；点击打开润色/再沟通结果卡。
+  canRefine: boolean;
+  onRefineSelection: () => void;
 }
 
 function Toolbar({
@@ -371,6 +413,8 @@ function Toolbar({
   liveMessage,
   onWrite,
   onStop,
+  canRefine,
+  onRefineSelection,
 }: ToolbarProps) {
   return (
     <div className="sticky bottom-0 z-10 border-t border-line bg-panel/95 px-4 py-2 backdrop-blur sm:px-6 sm:py-3">
@@ -388,6 +432,18 @@ function Toolbar({
             写本章
           </Button>
         )}
+        {!streaming ? (
+          <Button
+            onClick={onRefineSelection}
+            disabled={!canRefine}
+            variant="secondary"
+            size="sm"
+            title={canRefine ? undefined : "先在正文里选中一段再润色"}
+          >
+            <Wand2 className="h-4 w-4" aria-hidden="true" />
+            润色选段
+          </Button>
+        ) : null}
         {streaming ? (
           // ThinkingIndicator 自带 role=status，开始时播报一次「生成中」；
           // 易变字数 aria-hidden，仅供视觉，不逐 token 打扰屏读。