feat(capcut): 优化音频/字幕添加策略并重构语音切分逻辑

- 音频和字幕 API 调用改为先批量添加，批量失败时逐个兜底
- 重写 `splitIntoAudioSegments`，基于原始标点保留切分，合并短片段
- `qwen-tts.js` 补充中文逗号作为句末标点判断

.claude/skills/video-from-script/scripts/lib/capcut-tracks.js

@@ -10,8 +10,9 @@
  */
 
 const path = require('path')
-const { api, US } = require('./capcut-api')
-const { splitTextIntoSentences, loadAccountConfig: loadAccountConfigFromUtils } = require('./pipeline-utils')
+const fs = require('fs')
+const { api, US, getConfig } = require('./capcut-api')
+const { splitTextIntoSentences, loadAccountConfig: loadAccountConfigFromUtils, getManifestDir } = require('./pipeline-utils')
 
 // ============================================================================
 // 账号配置读取
@@ -314,17 +315,11 @@ async function addVideos(draftUrl, inputDir, items, timeline, width, height, tra
 // ============================================================================
 
 async function addSlots(draftUrl, items, timeline) {
-  const { api: capcutApi, US } = require('./capcut-api')
-  const { getManifestDir } = require('./pipeline-utils')
-  const path = require('path')
-
   // 获取当前云端草稿的 draft_content，获取第一个 video track 的 id
   let draftData
   try {
-    draftData = (await capcutApi('get_draft', { draft_url: draftUrl })).data || {}
+    draftData = (await api('get_draft', { draft_url: draftUrl })).data || {}
   } catch (err) {
-    // get_draft 接口不可用，尝试从本地 manifest 目录寻找草稿
-    const manifestDir = path.dirname(draftUrl.startsWith('http') ? draftUrl : '')
     console.log('   get_draft 不可用，切换本地写入模式')
     return addSlotsLocally(draftUrl, items, timeline)
   }
@@ -336,30 +331,12 @@ async function addSlots(draftUrl, items, timeline) {
     return
   }
 
-  // 构造 slot 数据
+  // 构造 slot 数据（复用 buildSlot）
   const slots = []
   for (let i = 0; i < items.length; i++) {
-    const item = items[i]
-    const tl = timeline[i]
-    const segId = item.segmentId || item._segmentId
+    const segId = items[i].segmentId || items[i]._segmentId
     if (!segId) continue
-
-    const slotId = generateUUID()
-    slots.push({
-      id: slotId,
-      material_id: segId,
-      track_id: videoTrack.id,
-      render_index: i,
-      type: 'video',
-      common_property: {
-        start_time: tl.start,
-        source_timerange: { start: 0, duration: tl.duration },
-        target_timerange: { start: tl.start, duration: tl.duration },
-        is_avatar: false,
-        audio_fade: { fade_in_duration: 0, fade_out_duration: 0 },
-        volume: 1.0,
-      },
-    })
+    slots.push(buildSlot(segId, videoTrack.id, i, timeline[i]))
   }
 
   if (slots.length === 0) {
@@ -369,13 +346,12 @@ async function addSlots(draftUrl, items, timeline) {
 
   // 通过 add_slots API 写入
   try {
-    await capcutApi('add_slots', {
+    await api('add_slots', {
       draft_url: draftUrl,
       slots: JSON.stringify(slots),
     })
     console.log(`   已写入 ${slots.length} 个 slot 到视频轨道`)
   } catch (err) {
-    // API 不支持时，降级为本地写入
     console.log(`   add_slots API 不可用: ${err.message}，降级为本地写入`)
     await addSlotsLocally(draftUrl, items, timeline, videoTrack.id)
   }
@@ -384,9 +360,6 @@ async function addSlots(draftUrl, items, timeline) {
 // 直接写入本地 draft_content.json 的 slot
 // options.draftId: 可选，直接指定 draftId（优先使用），否则从 draftUrl 提取
 async function addSlotsLocally(draftUrl, items, timeline, trackId, options = {}) {
-  const { api: capcutApi, US } = require('./capcut-api')
-  const fs = require('fs')
-
   // 优先使用 options.draftId，否则从 draftUrl 提取
   let draftId = options.draftId || null
   if (!draftId) {
@@ -403,7 +376,6 @@ async function addSlotsLocally(draftUrl, items, timeline, trackId, options = {})
     return
   }
 
-  const { getConfig } = require('./capcut-api')
   const jianyingPath = getConfig().jianyingDraftPath
   const draftPath = path.join(jianyingPath, draftId, 'draft_content.json')
   if (!fs.existsSync(draftPath)) {
@@ -461,7 +433,7 @@ async function addSlotsLocally(draftUrl, items, timeline, trackId, options = {})
   }
 }
 
-function buildSlot(segId, trackId, index, tl, US) {
+function buildSlot(segId, trackId, index, tl) {
   return {
     id: generateUUID(),
     material_id: segId,
@@ -548,17 +520,26 @@ async function addVoiceover(draftUrl, inputDir, items, timeline, audioUrls = {})
     return
   }
 
-  // 逐个添加音频（CapCut API 批量添加不稳定）
+  // 批量添加音频（同一轨道），失败时逐个兜底
   let addedCount = 0
-  for (const audioInfo of segmentsFlat) {
-    try {
-      await api('add_audios', {
-        draft_url: draftUrl,
-        audio_infos: JSON.stringify([audioInfo]),
-      })
-      addedCount++
-    } catch (err) {
-      console.error(`   音频添加失败: ${err.message.slice(0, 80)}`)
+  try {
+    await api('add_audios', {
+      draft_url: draftUrl,
+      audio_infos: JSON.stringify(segmentsFlat),
+    })
+    addedCount = segmentsFlat.length
+  } catch (err) {
+    console.log(`   批量添加音频失败 (${err.message.slice(0, 60)})，逐个添加...`)
+    for (const audioInfo of segmentsFlat) {
+      try {
+        await api('add_audios', {
+          draft_url: draftUrl,
+          audio_infos: JSON.stringify([audioInfo]),
+        })
+        addedCount++
+      } catch (e2) {
+        console.error(`   音频添加失败: ${e2.message.slice(0, 80)}`)
+      }
     }
   }
   const ossCount = segmentsFlat.filter(a => a.audio_url.startsWith('http')).length
@@ -702,18 +683,28 @@ async function addSubtitles(draftUrl, items, timeline, style = {}, split = false
     style_text: 0,
   }
 
-  // 逐条添加字幕（CapCut API 批量添加不稳定）
+  // 批量添加字幕（同一轨道），失败时逐条兜底
   let addedCount = 0
-  for (const cap of captions) {
-    try {
-      await api('add_captions', {
-        draft_url: draftUrl,
-        captions: JSON.stringify([cap]),
-        ...commonStyle,
-      })
-      addedCount++
-    } catch (err) {
-      console.error(`   字幕添加失败: ${err.message.slice(0, 80)}`)
+  try {
+    await api('add_captions', {
+      draft_url: draftUrl,
+      captions: JSON.stringify(captions),
+      ...commonStyle,
+    })
+    addedCount = captions.length
+  } catch (err) {
+    console.log(`   批量添加字幕失败 (${err.message.slice(0, 60)})，逐条添加...`)
+    for (const cap of captions) {
+      try {
+        await api('add_captions', {
+          draft_url: draftUrl,
+          captions: JSON.stringify([cap]),
+          ...commonStyle,
+        })
+        addedCount++
+      } catch (e2) {
+        console.error(`   字幕添加失败: ${e2.message.slice(0, 80)}`)
+      }
     }
   }
   console.log(`   已添加 ${addedCount}/${captions.length} 条字幕${split ? ' (分句模式)' : ''} (字体: ${style.font || '默认'}, 动画: ${animStyle.inAnimation || '无'} → ${animStyle.outAnimation || '无'})`)