feat(video-from-script): 重构工作流为子Agent分步执行并新增提示词模板系统

将视频制作工作流拆分为独立子步骤：分镜 → 图片提示词 → 生图 → 视频提示词 → 生视频 → 成片，每步由子Agent独立执行。引入prompts/目录统一管理提示词模板（分镜.md、图片提示词.md、视频提示词.md），通过account.json的storyboardPrompt/imageStylePrompt/videoStylePrompt字段引用。

变更内容：
- 新增confirmed机制和pipeline.js confirm命令，生图后必须人工确认才能继续
- manifest schema改用shotDesc/narration/duration/directorRef替代旧字段
- 文件命名规则从keyword改为slug（从shotDesc/narration派生）
- 删除旧的storyboard-rules.md和prompt-rules.md
- pipeline.js脚本拆分为lib/目录下的独立模块（cmd-init/cmd-confirm/cmd-validate/phase-*）
- 新增cmd-create-account支持一键创建带prompts目录的账号
- capcut_assemble支持narration字段替代text作为字幕源
- 新增.gitclaude/settings.json权限配置

.claude/skills/video-from-script/scripts/lib/cmd-init.js

@@ -0,0 +1,138 @@
+/**
+ * Command: init — 从 account.json + AI 创意内容生成规范 manifest.json
+ *
+ * 校验 items → 继承账号配置 → 创建输出目录 → 写出 manifest
+ */
+
+const fs = require('fs')
+const path = require('path')
+const { loadAccountConfig, saveManifest, ensureDir, ACCOUNTS_DIR, SKILLS_DIR } = require('./pipeline-utils')
+
+function initManifest(options) {
+  const { account: accountId, mode, items: itemsJson, itemsFile } = options
+
+  if (!accountId) {
+    console.error('错误: 必须指定 --account <账号ID>')
+    process.exit(1)
+  }
+
+  const accountConfig = loadAccountConfig(accountId)
+
+  // 解析 items
+  let rawItems
+  if (itemsFile) {
+    const filePath = path.resolve(itemsFile)
+    if (!fs.existsSync(filePath)) {
+      console.error(`错误: items 文件不存在: ${filePath}`)
+      process.exit(1)
+    }
+    rawItems = JSON.parse(fs.readFileSync(filePath, 'utf-8'))
+  } else if (itemsJson) {
+    rawItems = JSON.parse(itemsJson)
+  } else {
+    console.error('错误: 必须指定 --items <JSON> 或 --items-file <path>')
+    process.exit(1)
+  }
+
+  if (!Array.isArray(rawItems) || rawItems.length === 0) {
+    console.error('错误: items 必须是非空数组')
+    process.exit(1)
+  }
+
+  // 校验必填字段
+  const requiredFields = ['shotDesc', 'narration', 'imagePrompt']
+  const resolvedMode = mode || 'single'
+
+  for (let i = 0; i < rawItems.length; i++) {
+    const item = rawItems[i]
+    for (const f of requiredFields) {
+      if (!item[f]) {
+        console.error(`错误: items[${i}] 缺少必填字段 "${f}"`)
+        process.exit(1)
+      }
+    }
+    if (resolvedMode === 'framePair' && !item.lastFramePrompt) {
+      console.error(`错误: 首尾帧模式 items[${i}] 缺少 "lastFramePrompt"（imagePrompt 作为第一帧）`)
+      process.exit(1)
+    }
+  }
+
+  // 从 account.json 继承参考图
+  const styles = accountConfig.styles || {}
+  const firstStyleKey = Object.keys(styles)[0]
+  const styleRefs = firstStyleKey ? (styles[firstStyleKey].references || []) : []
+  const references = styleRefs.map(ref => {
+    const entry = {}
+    if (ref.file) entry.file = path.join(ACCOUNTS_DIR, accountId, 'references', ref.file)
+    if (ref.url) entry.url = ref.url
+    return entry
+  })
+
+  // 构建 items
+  const items = rawItems.map((raw, i) => {
+    const item = {
+      id: i + 1,
+      status: 'pending',
+      shotDesc: raw.shotDesc || '',
+      narration: raw.narration || raw.text || '',
+      duration: raw.duration || 5,
+      imagePrompt: raw.imagePrompt,
+      confirmed: false,
+    }
+    if (raw.directorRef) item.directorRef = raw.directorRef
+    if (raw.videoPrompt) item.videoPrompt = raw.videoPrompt
+    if (resolvedMode === 'framePair') item.lastFramePrompt = raw.lastFramePrompt
+    return item
+  })
+
+  // 组装 manifest
+  const manifest = {
+    account: accountId,
+    imageModel: accountConfig.imageModel || 'gemini',
+    videoModel: accountConfig.videoModel || 'veo3-fast-frames',
+    format: accountConfig.defaultFormat || '9:16',
+    mode: resolvedMode,
+    references,
+    items,
+  }
+
+  // 创建输出目录（自增序号）
+  const date = new Date()
+  const dateStr = [
+    date.getFullYear(),
+    String(date.getMonth() + 1).padStart(2, '0'),
+    String(date.getDate()).padStart(2, '0'),
+  ].join('')
+  const prefix = `${accountConfig.name}_${dateStr}`
+  const outputBase = path.join(SKILLS_DIR, '..', '..', '..', 'output')
+  ensureDir(outputBase)
+
+  let seq = 1
+  while (fs.existsSync(path.join(outputBase, `${prefix}_${String(seq).padStart(3, '0')}`))) {
+    seq++
+  }
+  const dirName = `${prefix}_${String(seq).padStart(3, '0')}`
+  const outputDir = path.join(outputBase, dirName)
+  ensureDir(outputDir)
+  ensureDir(path.join(outputDir, 'images'))
+  ensureDir(path.join(outputDir, 'videos'))
+  ensureDir(path.join(outputDir, 'audio'))
+
+  const manifestPath = path.join(outputDir, 'manifest.json')
+  saveManifest(manifestPath, manifest)
+
+  console.log(`\nManifest 已创建: ${manifestPath}`)
+  console.log(`  账号: ${accountId} (${accountConfig.name})`)
+  console.log(`  模型: ${manifest.imageModel} + ${manifest.videoModel}`)
+  console.log(`  画幅: ${manifest.format}, 模式: ${manifest.mode}`)
+  console.log(`  Items: ${items.length}`)
+  console.log(`  参考图: ${references.length}`)
+  if (items.some(it => !it.videoPrompt)) {
+    console.log(`  ⚠ ${items.filter(it => !it.videoPrompt).length} 个 item 缺少 videoPrompt，生视频阶段将跳过`)
+  }
+  console.log()
+
+  return manifestPath
+}
+
+module.exports = { initManifest }