fix(#1677): AI Review 反馈修复——标题校验/TTS依赖收窄/排序健壮性/预览数硬上限

- 单视频标题校验与 buildPayload.validateGenerateInputs 对齐：aiAutoSelect
  自动模式允许空标题（后端生成，既有设计），手动模式必填，逻辑显式化
- TTS 试听 effect 依赖收窄到 previewTitles[0]（variant0Title），编辑其他
  变体标题不再触发多余 TTS 请求
- BatchGenerationGrid 排序加 (variantIndex || 0) 兜底防 NaN
- CanvasPreviewGrid 渲染数加 MAX_PREVIEW_COUNT(10) 硬上限，防媒体元素过多卡顿

apps/web/src/pages/generate/GeneratePage.tsx

@@ -132,6 +132,8 @@ const GeneratePage: React.FC = () => {
 
   const [previewVoiceAudioUrl, setPreviewVoiceAudioUrl] = useState<string | null>(null)
   const ttsAbortRef = useRef<AbortController | null>(null)
+  // TTS 试听文案：批量跟随变体0标题（仅取首项，避免编辑其他变体标题触发多余 TTS 请求）
+  const variant0Title = isBatch ? previewTitles[0] || "" : ""
 
   useEffect(() => {
     const voiceAsset = voiceMaterials.find((m) => m.id === selectedVoice)
@@ -141,7 +143,7 @@ const GeneratePage: React.FC = () => {
     }
 
     // 批量模式下 TTS 文案跟随变体0标题；单视频跟随主标题
-    const ttsTitle = isBatch ? previewTitles[0] || "" : titleSettings.title
+    const ttsTitle = isBatch ? variant0Title || "" : titleSettings.title
     const voiceId = selectedClonedVoice || selectedVoice
     if (!voiceId || !ttsTitle) {
       setPreviewVoiceAudioUrl(null)
@@ -174,7 +176,7 @@ const GeneratePage: React.FC = () => {
     selectedVoice,
     selectedClonedVoice,
     titleSettings.title,
-    previewTitles,
+    variant0Title,
     isBatch,
     voiceMaterials,
   ])
@@ -321,9 +323,13 @@ const GeneratePage: React.FC = () => {
         message.warning("请为每个勾选的视频输入标题")
         return
       }
-    } else if (!titleSettings.aiAutoSelect && !titleSettings.title?.trim()) {
-      message.warning("请先选择或输入标题")
-      return
+    } else if (!titleSettings.title?.trim()) {
+      // 与 buildPayload.validateGenerateInputs 一致：AI 自动选标题模式（aiAutoSelect）
+      // 允许空标题由后端生成；手动模式必须填写，避免提交空标题
+      if (!titleSettings.aiAutoSelect) {
+        message.warning("请先选择或输入标题")
+        return
+      }
     }
     if (!previewReady) {
       message.warning("预览素材正在加载，请稍候")

apps/web/src/pages/generate/components/BatchGenerationGrid.tsx

@@ -22,7 +22,7 @@ const BatchGenerationGrid: React.FC<BatchGenerationGridProps> = ({
   titles,
   onRetryTask,
 }) => {
-  const sorted = [...tasks].sort((a, b) => a.variantIndex - b.variantIndex)
+  const sorted = [...tasks].sort((a, b) => (a.variantIndex || 0) - (b.variantIndex || 0))
 
   return (
     <div className="xx-form-section">

apps/web/src/pages/generate/components/CanvasPreviewGrid.tsx

@@ -12,6 +12,7 @@ import type { AssetItem } from "@/api/assets"
 import type { EditingTemplate } from "@/api/editing-planner"
 import type { TitleSettings } from "../types"
 import FrontendPreviewPlayer from "./FrontendPreviewPlayer"
+import { MAX_PREVIEW_COUNT } from "../constants"
 
 interface CanvasPreviewGridProps {
   count: number
@@ -41,9 +42,11 @@ const CanvasPreviewGrid: React.FC<CanvasPreviewGridProps> = ({
   onToggleSelect,
   selectable = true,
 }) => {
+  // 硬上限保护：同时播放的媒体元素数量不超过 MAX_PREVIEW_COUNT（10），避免浏览器卡顿
+  const safeCount = Math.max(1, Math.min(count, MAX_PREVIEW_COUNT))
   return (
     <div className="xx-canvas-grid">
-      {Array.from({ length: count }, (_, i) => {
+      {Array.from({ length: safeCount }, (_, i) => {
         const checked = selectedIds.includes(i)
         return (
           <div