feat: Add PDF viewer

web/src/apps/PdfViewer/PdfViewer.tsx

@@ -0,0 +1,74 @@
+import React, { useEffect, useState } from 'react';
+import { Spin, Result, Button } from 'antd';
+import type { AppComponentProps } from '../types';
+import { vfsApi } from '../../api/client';
+
+export const PdfViewerApp: React.FC<AppComponentProps> = ({ filePath, onRequestClose }) => {
+  const [url, setUrl] = useState<string>();
+  const [loading, setLoading] = useState(true);
+  const [err, setErr] = useState<string>();
+
+  useEffect(() => {
+    let cancelled = false;
+    setLoading(true);
+    setErr(undefined);
+    setUrl(undefined);
+
+    vfsApi.getTempLinkToken(filePath.replace(/^\/+/, ''))
+      .then(res => {
+        if (cancelled) return;
+        const publicUrl = vfsApi.getTempPublicUrl(res.token);
+        setUrl(publicUrl + '#toolbar=1&navpanes=1');
+      })
+      .catch(e => {
+        if (!cancelled) setErr(e.message || '获取临时链接失败');
+      })
+      .finally(() => {
+        if (!cancelled) setLoading(false);
+      });
+
+    return () => { cancelled = true; };
+  }, [filePath]);
+
+  if (loading) {
+    return (
+      <div style={{ width: '100%', height: '100%', display: 'flex', alignItems: 'center', justifyContent: 'center' }}>
+        <Spin tip="正在加载 PDF..." />
+      </div>
+    );
+  }
+  if (err) {
+    return (
+      <Result
+        status="error"
+        title="无法加载 PDF"
+        subTitle={err}
+        extra={<Button type="primary" onClick={onRequestClose}>关闭</Button>}
+      />
+    );
+  }
+
+  if (!url) {
+    return (
+      <Result
+        status="warning"
+        title="无可用链接"
+        subTitle="未能生成 PDF 的临时访问链接"
+        extra={<Button type="primary" onClick={onRequestClose}>关闭</Button>}
+      />
+    );
+  }
+
+  return (
+    <div style={{ width: '100%', height: '100%', background: 'var(--ant-color-bg-container, #fff)' }}>
+      <iframe
+        src={url}
+        width="100%"
+        height="100%"
+        title="PDF Viewer"
+        style={{ border: 'none' }}
+      />
+    </div>
+  );
+};
+

web/src/apps/PdfViewer/index.ts

@@ -0,0 +1,16 @@
+import type { AppDescriptor } from '../types';
+import { PdfViewerApp } from './PdfViewer';
+
+export const descriptor: AppDescriptor = {
+  key: 'pdf-viewer',
+  name: 'PDF 查看器',
+  supported: (entry) => {
+    if (entry.is_dir) return false;
+    const ext = entry.name.split('.').pop()?.toLowerCase() || '';
+    return ext === 'pdf';
+  },
+  component: PdfViewerApp,
+  default: true,
+  defaultBounds: { width: 1024, height: 768, x: 160, y: 100 },
+};
+