fix(desktop): selection回填只留用户意见+圈选截图，去掉selector/DOM/页面噪音

圈选标注截图作为引用承载元素位置；输入框文字只放用户修改意见+具体改动(人话)，
不再写 selector/nthPath/computedStyles/页面URL/「请在源码中落地」。沿用进输入框+手动发送。

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

desktop/src/lib/previewEvents.test.ts

@@ -32,7 +32,7 @@ describe('subscribePreviewEvents', () => {
     const payload = { pageUrl: 'http://x/', element: { selector: '#t', tag: 'h1', classes: [] }, change: { description: '改一下' }, screenshot: { dataUrl: 'data:image/png;base64,AAAA', kind: 'element' } }
     listeners['preview://event']!({ payload: JSON.stringify({ v: 1, type: 'selection', payload }) })
     expect(prefill).toHaveBeenCalledWith('s1', expect.objectContaining({
-      text: expect.stringContaining('#t'),
+      text: expect.stringContaining('改一下'),
       attachments: [expect.objectContaining({ type: 'image', data: 'data:image/png;base64,AAAA' })],
     }))
   })

desktop/src/lib/selectionComposer.test.ts

@@ -1,15 +1,26 @@
 import { expect, it } from 'vitest'
 import { buildSelectionComposerText } from './selectionComposer'
 
-it('renders a readable block with locator + change + source', () => {
+it('renders only the user instruction + concrete changes (no selector/DOM/page noise)', () => {
   const text = buildSelectionComposerText({
     pageUrl: 'http://127.0.0.1:4321/preview-fs/s1/index.html',
     sourceHint: 'index.html',
     element: { selector: '#title', tag: 'h1', text: '模型还没用熟', classes: [] } as never,
     change: { text: { from: '模型还没用熟', to: '模型用熟了' }, description: '标题改积极一点' } as never,
   })
-  expect(text).toContain('#title')
-  expect(text).toContain('index.html')
-  expect(text).toContain('模型用熟了')
+  // 用户的话 + 具体改动在
   expect(text).toContain('标题改积极一点')
+  expect(text).toContain('模型用熟了')
+  // selector / 页面 URL / 「请在源码中落地」 等 DOM 噪音不在（截图才是引用）
+  expect(text).not.toContain('#title')
+  expect(text).not.toContain('index.html')
+  expect(text).not.toContain('请在源码中落地')
+})
+
+it('returns empty text when there is no description or change (image alone is the reference)', () => {
+  const text = buildSelectionComposerText({
+    pageUrl: 'http://x/',
+    element: { selector: '#t', tag: 'div', classes: [] } as never,
+  })
+  expect(text).toBe('')
 })

desktop/src/lib/selectionComposer.ts

@@ -7,18 +7,20 @@ export type SelectionPayload = {
   change?: EditDiff & { description?: string }
 }
 
+/**
+ * 选中元素的「引用」由随附的圈选标注截图承载（截图里已把元素圈出来）。
+ * 这里只产出用户的修改意见 + 具体改动（人话），**不再**把 selector / DOM 定位 /
+ * computedStyles / 页面 URL 等写进输入框 —— 那些 DOM 噪音交互体验差，且图片已是引用。
+ * 无描述、无改动时返回空串（让图片单独作为引用进输入框）。
+ */
 export function buildSelectionComposerText(p: SelectionPayload): string {
-  const lines: string[] = []
-  lines.push(`针对页面元素 \`${p.element.selector}\`（${p.element.tag}${p.element.text ? `，文本「${p.element.text}」` : ''}）：`)
-  if (p.sourceHint) lines.push(`- 来源：${p.sourceHint}`)
-  lines.push(`- 页面：${p.pageUrl}`)
   const c = p.change
+  const lines: string[] = []
+  if (c?.description) lines.push(c.description)
   if (c?.text) lines.push(`- 文本：「${c.text.from}」→「${c.text.to}」`)
   if (c?.color) lines.push(`- 文字颜色：${c.color.from} → ${c.color.to}`)
   if (c?.background) lines.push(`- 背景：${c.background.from} → ${c.background.to}`)
   if (c?.opacity) lines.push(`- 不透明度：${c.opacity.from} → ${c.opacity.to}`)
   if (c?.fontFamily) lines.push(`- 字体：${c.fontFamily.from} → ${c.fontFamily.to}`)
-  if (c?.description) lines.push(`- 说明：${c.description}`)
-  lines.push('请在源码中落地以上修改。')
   return lines.join('\n')
 }