refactor(agent): 将 tools 模块拆分为独立文件并优化导入路径

将 `tools.ts` 拆分为按功能划分的独立文件，并存放于 `tools/` 目录下，同时更新导入路径；优化 agent 系统提示语，移除冗余的「美图 Agent」前缀。

web/server/agent/tools/list-outputs.ts

@@ -0,0 +1,46 @@
+import fs from 'fs';
+import path from 'path';
+import { OUTPUT_DIR, loadJSON } from './shared';
+import type { ToolDefinition } from './types';
+
+export const listOutputs: ToolDefinition = {
+  name: 'list_outputs',
+  description: '列出 output 目录下所有项目及其 manifest 状态，方便查看历史生成记录和进行中的任务。',
+  input_schema: {
+    type: 'object',
+    properties: {},
+    required: [],
+  },
+  execute: async () => {
+    if (!fs.existsSync(OUTPUT_DIR)) return 'output 目录不存在';
+    const entries = fs.readdirSync(OUTPUT_DIR, { withFileTypes: true })
+      .filter((d) => d.isDirectory())
+      .map((d) => {
+        const manifestPath = path.join(OUTPUT_DIR, d.name, 'manifest.json');
+        if (!fs.existsSync(manifestPath)) return { name: d.name, status: 'no manifest' };
+        try {
+          const manifest = loadJSON(manifestPath) as {
+            account?: string;
+            imageModel?: string;
+            videoModel?: string;
+            mode?: string;
+            pipeline?: { phases?: Record<string, string> };
+            items?: Array<{ status?: string }>;
+          };
+          const phases = manifest.pipeline?.phases || {};
+          const itemCount = manifest.items?.length || 0;
+          const doneCount = manifest.items?.filter((i) => i.status === 'done').length || 0;
+          return {
+            name: d.name,
+            account: manifest.account || '?',
+            mode: manifest.mode || '?',
+            items: `${doneCount}/${itemCount} done`,
+            phases: Object.entries(phases).map(([k, v]) => `${k}:${v}`).join(', ') || 'pending',
+          };
+        } catch {
+          return { name: d.name, status: 'manifest parse error' };
+        }
+      });
+    return JSON.stringify(entries, null, 2);
+  },
+};