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/pipeline-utils.js

@@ -0,0 +1,170 @@
+/**
+ * Pipeline 共享工具函数与路径常量
+ *
+ * 所有 phase/command 模块共用：配置加载、文件操作、路径计算、日志
+ */
+
+const fs = require('fs')
+const path = require('path')
+
+// 路径常量（基于 lib/ 的父目录 scripts/）
+const SCRIPTS_DIR = path.join(__dirname, '..')
+const SKILLS_DIR = path.join(SCRIPTS_DIR, '..')
+const PROJECT_ROOT = path.join(SKILLS_DIR, '..', '..')
+const CONFIG_PATH = path.join(SKILLS_DIR, 'config.json')
+const ACCOUNTS_DIR = path.join(PROJECT_ROOT, 'accounts')
+
+// ============================================================================
+// 配置 & Manifest
+// ============================================================================
+
+function loadConfig() {
+  return JSON.parse(fs.readFileSync(CONFIG_PATH, 'utf-8'))
+}
+
+function loadManifest(manifestPath) {
+  return JSON.parse(fs.readFileSync(manifestPath, 'utf-8'))
+}
+
+function saveManifest(manifestPath, manifest) {
+  const tmp = manifestPath + '.tmp'
+  fs.writeFileSync(tmp, JSON.stringify(manifest, null, 2), 'utf-8')
+  fs.renameSync(tmp, manifestPath)
+}
+
+function loadAccountConfig(accountId) {
+  const accountPath = path.join(ACCOUNTS_DIR, accountId, 'account.json')
+  if (!fs.existsSync(accountPath)) throw new Error(`账号不存在: ${accountPath}`)
+  return JSON.parse(fs.readFileSync(accountPath, 'utf-8'))
+}
+
+// ============================================================================
+// 参考图解析
+// ============================================================================
+
+function getReferences(manifest, accountConfig) {
+  const result = { localPaths: [], urls: [] }
+  const accountId = accountConfig.id || manifest.account || ''
+
+  // 优先读 manifest.references（agent 创建时写入）
+  const refs = manifest.references || []
+  if (refs.length > 0) {
+    for (const ref of refs) {
+      if (ref.url) result.urls.push(ref.url)
+      if (ref.file) {
+        const localPath = path.isAbsolute(ref.file) ? ref.file : path.resolve(ref.file)
+        if (fs.existsSync(localPath)) {
+          result.localPaths.push(localPath)
+        } else {
+          log('images', `参考图不存在: ${ref.file}`)
+        }
+      }
+    }
+    if (result.localPaths.length > 0 || result.urls.length > 0) return result
+    log('images', 'manifest.references 全部无效，尝试 account fallback')
+  }
+
+  // Fallback 1: 从 account.json 的 styles.*.references 读取
+  const styles = accountConfig.styles || {}
+  for (const [, style] of Object.entries(styles)) {
+    for (const ref of (style.references || [])) {
+      if (ref.url) result.urls.push(ref.url)
+      if (ref.file && accountId) {
+        const localPath = path.join(ACCOUNTS_DIR, accountId, 'references', ref.file)
+        if (fs.existsSync(localPath)) {
+          result.localPaths.push(localPath)
+        }
+      }
+    }
+  }
+  if (result.localPaths.length > 0 || result.urls.length > 0) return result
+
+  // Fallback 2: 扫描 account 的 references 目录
+  if (accountId) {
+    const refDir = path.join(ACCOUNTS_DIR, accountId, 'references')
+    if (fs.existsSync(refDir)) {
+      const files = fs.readdirSync(refDir).filter(f =>
+        /\.(png|jpg|jpeg|webp)$/i.test(f)
+      )
+      for (const f of files) {
+        result.localPaths.push(path.join(refDir, f))
+      }
+      if (files.length > 0) {
+        log('images', `从 references 目录兜底扫描到 ${files.length} 个参考图`)
+      }
+    }
+  }
+
+  if (result.localPaths.length === 0 && result.urls.length === 0) {
+    log('images', '无参考图，将使用纯文生图模式')
+  }
+
+  return result
+}
+
+// ============================================================================
+// 文件操作
+// ============================================================================
+
+function ensureDir(dir) {
+  fs.mkdirSync(dir, { recursive: true })
+}
+
+function slugify(text) {
+  return text
+    .replace(/[^\w一-鿿]/g, '_')
+    .replace(/_+/g, '_')
+    .replace(/^_|_$/g, '')
+    .substring(0, 20)
+}
+
+function renameGeneratedFile(oldRelPath, dir, seq, nameHint, suffix) {
+  if (!oldRelPath) return oldRelPath
+  const oldAbs = path.resolve(dir, oldRelPath)
+  if (!fs.existsSync(oldAbs)) return oldRelPath
+  const ext = path.extname(oldAbs)
+  const slug = nameHint ? slugify(nameHint) : ''
+  const tag = suffix ? `_${suffix}` : ''
+  const newName = slug
+    ? `scene_${String(seq).padStart(2, '0')}_${slug}${tag}${ext}`
+    : `scene_${String(seq).padStart(2, '0')}${tag}${ext}`
+  const newAbs = path.join(path.dirname(oldAbs), newName)
+  if (oldAbs !== newAbs) {
+    try { fs.renameSync(oldAbs, newAbs) } catch (_) { return oldRelPath }
+  }
+  return path.relative(dir, newAbs).replace(/\\/g, '/')
+}
+
+// ============================================================================
+// 日志 & 路径
+// ============================================================================
+
+function log(phase, msg) {
+  console.log(`[${phase}] ${msg}`)
+}
+
+function getManifestDir(manifestPath) {
+  return path.dirname(path.resolve(manifestPath))
+}
+
+// ============================================================================
+// Exports
+// ============================================================================
+
+module.exports = {
+  SCRIPTS_DIR,
+  SKILLS_DIR,
+  PROJECT_ROOT,
+  CONFIG_PATH,
+  ACCOUNTS_DIR,
+  loadConfig,
+  loadManifest,
+  saveManifest,
+  loadAccountConfig,
+  getReferences,
+  ensureDir,
+  slugify,
+  renameGeneratedFile,
+  log,
+  getManifestDir,
+}