feat(ai-writing): 支持用户粘贴已有大纲并按结构生成

表单可提交 userOutline，后端解析/归一用户大纲并关联素材；补充大纲测试用例与右侧编辑器滑词/段落菜单文档。

frontend-web/src/open-canvas/components/ai-writing/AIWritingForm.tsx

@@ -50,6 +50,8 @@ export function AIWritingForm({
   hideAdvancedFields = false,
 }: AIWritingFormProps) {
   const [intent, setIntent] = useState('');
+  const [showOutline, setShowOutline] = useState(false);
+  const [outlineText, setOutlineText] = useState('');
   const [articleType, setArticleType] = useState('analysis');
   const [audience, setAudience] = useState('普通读者');
   const [wordCountInput, setWordCountInput] = useState('800');
@@ -115,6 +117,7 @@ export function AIWritingForm({
     const wordCount = Math.max(100, parseInt(wordCountInput, 10) || 800);
     onSubmit({
       userIntent: intent.trim(),
+      userOutline: outlineText.trim() || undefined,
       articleType,
       targetAudience: hideAdvancedFields
         ? DEFAULT_AUDIENCE
@@ -155,6 +158,43 @@ export function AIWritingForm({
           />
         </div>
 
+        <div className="mt-4 space-y-2">
+          <button
+            type="button"
+            onClick={() => setShowOutline((v) => !v)}
+            disabled={disabled}
+            className="flex w-full items-center justify-between text-left"
+          >
+            <span className={FIELD_LABEL_CLASS}>
+              已有大纲
+              <span className="ml-1 text-sm font-normal text-muted-foreground dark:text-white/70">
+                （可选）
+              </span>
+            </span>
+            <span className="text-sm text-muted-foreground dark:text-white/70">
+              {showOutline ? '收起 ▴' : '我已有大纲，直接粘贴 ▾'}
+            </span>
+          </button>
+          {showOutline && (
+            <>
+              <Textarea
+                placeholder={
+                  '粘贴你已有的大纲，将完全按你的大纲生成（支持一/二/三级目录）。例如：\n' +
+                  '一、引言\n（一）背景\n（二）意义\n二、现状分析\n…'
+                }
+                value={outlineText}
+                onChange={(e) => setOutlineText(e.target.value)}
+                disabled={disabled}
+                rows={6}
+                className="resize-none rounded-2xl border-[#e8dedd] bg-white px-4 py-3 text-sm leading-6 shadow-sm"
+              />
+              <p className="text-xs leading-relaxed text-muted-foreground/80">
+                填写后将跳过自动大纲规划，按你粘贴的大纲逐章生成；留空则由 AI 自动规划大纲。
+              </p>
+            </>
+          )}
+        </div>
+
         <div className="mt-4 grid grid-cols-2 gap-4">
           <div className="min-w-0 space-y-2">
             <label className={FIELD_LABEL_CLASS}>文章类型</label>

frontend-web/src/open-canvas/contexts/AIWritingContext.tsx

@@ -259,6 +259,8 @@ export function AIWritingProvider({ children }: { children: ReactNode }) {
       await stream.submit(
         {
           user_intent: request.userIntent,
+          // 用户自带大纲原文（留空则后端走自动规划）
+          user_outline_raw: request.userOutline?.trim() || '',
           article_type: request.articleType,
           target_audience: request.targetAudience,
           word_count_target: request.wordCountTarget,

frontend-web/src/open-canvas/hooks/useAIWritingStream.ts

@@ -623,6 +623,7 @@ export function interruptToEvent(value: unknown, sessionId: string): ProgressEve
 
 export type AIWritingValues = {
   user_intent?: string;
+  user_outline_raw?: string;
   article_type?: string;
   status?: string;
   material_package?: unknown;

frontend-web/src/open-canvas/types/ai-writing.ts

@@ -220,6 +220,8 @@ export interface UserInterventionPayload {
 
 export interface AIWritingRequest {
   userIntent: string;
+  /** 用户粘贴的「已有大纲」原文（可选）。非空时后端按此大纲生成，不再自动规划 */
+  userOutline?: string;
   articleType: string;
   targetAudience: string;
   wordCountTarget: number;