feat(agent): 添加视频创作工作流技能系统和流程工具

新增基于 SKILL.md 的视频创作工作流系统，Agent 可通过 skills 目录加载结构化的导演指令；实现 validate_storyboard、update_manifest_items、confirm_images 三个流程工具支撑分镜校验、提示词更新和图片确认。

web/server/agent/tools/validate-storyboard.ts

@@ -0,0 +1,70 @@
+import type { ToolDefinition } from './types';
+
+export const validateStoryboard: ToolDefinition = {
+  name: 'validate_storyboard',
+  description: '校验分镜脚本质量：TTS 估算 ≤ 6s、ratio 预检、script 拼接校验。返回校验结果和问题列表。',
+  input_schema: {
+    type: 'object',
+    properties: {
+      items: { type: 'string', description: '分镜 JSON 数组字符串，每个元素需包含 shotDesc、script 字段，可选 duration、directorRef' },
+      videoModelDuration: { type: 'number', description: '视频模型固定时长（秒），默认 6' },
+    },
+    required: ['items'],
+  },
+  execute: async (params) => {
+    const { items, videoModelDuration = 6 } = params as { items: string; videoModelDuration?: number };
+    let parsed: any[];
+    try { parsed = JSON.parse(items); } catch { return '错误: items 不是合法 JSON'; }
+    if (!Array.isArray(parsed) || parsed.length === 0) return '错误: items 必须是非空数组';
+
+    const errors: string[] = [];
+    const warnings: string[] = [];
+    const TTS_SPEED = 1.15;
+    const CHARS_PER_SEC = 5;
+
+    for (const item of parsed) {
+      const idx = item.id ?? parsed.indexOf(item) + 1;
+      const script: string = item.script || '';
+      const charCount = script.length;
+      const ttsEstimate = charCount / CHARS_PER_SEC;
+      const audioDur = ttsEstimate * TTS_SPEED;
+      const ratio = videoModelDuration / audioDur;
+
+      if (!item.shotDesc) errors.push(`Shot ${idx}: 缺少 shotDesc`);
+      if (!script) errors.push(`Shot ${idx}: 缺少 script`);
+
+      // TTS 估算检查
+      if (ttsEstimate > 6) {
+        errors.push(`Shot ${idx}: TTS 估算 ${ttsEstimate.toFixed(1)}s > 6s，必须拆分 (script: ${script.slice(0, 30)}...)`);
+      }
+
+      // ratio 预检
+      if (ratio < 0.9) {
+        errors.push(`Shot ${idx}: ratio ${ratio.toFixed(2)} < 0.9，音频太长需拆分 (audio=${audioDur.toFixed(1)}s, video=${videoModelDuration}s)`);
+      }
+
+      if (!item.directorRef) {
+        warnings.push(`Shot ${idx}: 建议填写 directorRef`);
+      }
+    }
+
+    // script 拼接校验 - 返回统计而非原文比对（原文由用户提供）
+    const totalChars = parsed.reduce((sum: number, i: any) => sum + (i.script?.length || 0), 0);
+    const totalAudio = (totalChars / CHARS_PER_SEC) * TTS_SPEED;
+
+    const result = {
+      valid: errors.length === 0,
+      shotCount: parsed.length,
+      totalChars,
+      estimatedTotalAudio: `${totalAudio.toFixed(1)}s`,
+      errors,
+      warnings,
+    };
+
+    if (errors.length > 0) {
+      return `❌ 分镜校验未通过 (${errors.length} 个问题):\n\n${errors.map((e, i) => `${i + 1}. ${e}`).join('\n')}${warnings.length ? `\n\n⚠️ 警告:\n${warnings.map((w, i) => `${i + 1}. ${w}`).join('\n')}` : ''}\n\n统计: ${parsed.length} 个镜头, 总字数 ${totalChars}, 音频估算 ${totalAudio.toFixed(1)}s`;
+    }
+
+    return `✅ 分镜校验通过\n\n统计: ${parsed.length} 个镜头, 总字数 ${totalChars}, 音频估算 ${totalAudio.toFixed(1)}s${warnings.length ? `\n\n⚠️ 警告:\n${warnings.map((w, i) => `${i + 1}. ${w}`).join('\n')}` : ''}`;
+  },
+};