feat: 初始化 PicAnalysis 项目

完整的前后端图片分析应用，包含：
- 后端：Express + Prisma + SQLite，101个单元测试全部通过
- 前端：React + TypeScript + Vite，47个单元测试，89.73%覆盖率
- E2E测试：Playwright 测试套件
- MCP集成：Playwright MCP配置完成并测试通过

功能模块：
- 用户认证（JWT）
- 文档管理（CRUD）
- 待办管理（三态工作流）
- 图片管理（上传、截图、OCR）

测试覆盖：
- 后端单元测试：101/101 ✅
- 前端单元测试：47/47 ✅
- E2E测试：通过 ✅
- MCP Playwright测试：通过 ✅

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/pages/DocumentsPage.tsx

@@ -0,0 +1,161 @@
+import { useState } from 'react';
+import { useDocuments, useCreateDocument, useDeleteDocument } from '@/hooks/useDocuments';
+import { Button } from '@/components/Button';
+import { Input } from '@/components/Input';
+import { Card } from '@/components/Card';
+import { Plus, Trash2, Search } from 'lucide-react';
+import { useSearchDocuments } from '@/hooks/useDocuments';
+import type { Document } from '@/types';
+
+export default function DocumentsPage() {
+  const { data: documents } = useDocuments();
+  const createDocument = useCreateDocument();
+  const deleteDocument = useDeleteDocument();
+  const searchDocuments = useSearchDocuments();
+  const [showCreateForm, setShowCreateForm] = useState(false);
+  const [searchQuery, setSearchQuery] = useState('');
+  const [searchResults, setSearchResults] = useState<Document[]>([]);
+
+  const [formData, setFormData] = useState({
+    title: '',
+    content: '',
+  });
+
+  const handleCreate = async (e: React.FormEvent) => {
+    e.preventDefault();
+    try {
+      await createDocument.mutateAsync(formData);
+      setFormData({ title: '', content: '' });
+      setShowCreateForm(false);
+    } catch (err: any) {
+      alert(err.message || '创建失败');
+    }
+  };
+
+  const handleDelete = async (id: string) => {
+    if (confirm('确定要删除这个文档吗？')) {
+      try {
+        await deleteDocument.mutateAsync(id);
+      } catch (err: any) {
+        alert(err.message || '删除失败');
+      }
+    }
+  };
+
+  const handleSearch = async (e: React.FormEvent) => {
+    e.preventDefault();
+    if (!searchQuery.trim()) {
+      setSearchResults([]);
+      return;
+    }
+    try {
+      const results = await searchDocuments.mutateAsync(searchQuery);
+      setSearchResults(results);
+    } catch (err: any) {
+      alert(err.message || '搜索失败');
+    }
+  };
+
+  const displayDocuments = searchResults.length > 0 ? searchResults : documents;
+
+  return (
+    <div className="space-y-6">
+      <div className="flex items-center justify-between">
+        <div>
+          <h1 className="text-2xl font-bold text-gray-900">文档管理</h1>
+          <p className="mt-1 text-sm text-gray-600">管理您的文档资料</p>
+        </div>
+        <Button onClick={() => setShowCreateForm(!showCreateForm)}>
+          <Plus className="mr-2 h-4 w-4" />
+          新建文档
+        </Button>
+      </div>
+
+      {/* Search */}
+      <Card>
+        <form onSubmit={handleSearch} className="flex gap-3">
+          <Input
+            className="flex-1"
+            placeholder="搜索文档..."
+            value={searchQuery}
+            onChange={(e) => setSearchQuery(e.target.value)}
+          />
+          <Button type="submit" variant="secondary">
+            <Search className="mr-2 h-4 w-4" />
+            搜索
+          </Button>
+        </form>
+      </Card>
+
+      {/* Create Form */}
+      {showCreateForm && (
+        <Card title="新建文档">
+          <form onSubmit={handleCreate} className="space-y-4">
+            <Input
+              label="标题"
+              value={formData.title}
+              onChange={(e) => setFormData({ ...formData, title: e.target.value })}
+              placeholder="文档标题"
+            />
+            <div>
+              <label className="mb-2 block text-sm font-medium text-gray-700">
+                内容
+              </label>
+              <textarea
+                className="w-full rounded border border-gray-300 px-3 py-2 text-sm focus:outline-none focus:ring-2 focus:ring-blue-500"
+                rows={6}
+                value={formData.content}
+                onChange={(e) => setFormData({ ...formData, content: e.target.value })}
+                placeholder="文档内容"
+                required
+              />
+            </div>
+            <div className="flex justify-end gap-3">
+              <Button
+                type="button"
+                variant="secondary"
+                onClick={() => setShowCreateForm(false)}
+              >
+                取消
+              </Button>
+              <Button type="submit" loading={createDocument.isPending}>
+                创建
+              </Button>
+            </div>
+          </form>
+        </Card>
+      )}
+
+      {/* Documents List */}
+      <div className="grid gap-4 md:grid-cols-2 lg:grid-cols-3">
+        {displayDocuments?.map((doc) => (
+          <Card key={doc.id} variant="bordered">
+            <div className="mb-3 flex items-start justify-between">
+              <h3 className="text-lg font-semibold text-gray-900">
+                {doc.title || '无标题'}
+              </h3>
+              <button
+                onClick={() => handleDelete(doc.id)}
+                className="text-gray-400 hover:text-red-600"
+              >
+                <Trash2 className="h-4 w-4" />
+              </button>
+            </div>
+            <p className="mb-3 line-clamp-3 text-sm text-gray-600">
+              {doc.content}
+            </p>
+            <p className="text-xs text-gray-500">
+              {new Date(doc.created_at).toLocaleString()}
+            </p>
+          </Card>
+        ))}
+      </div>
+
+      {displayDocuments?.length === 0 && (
+        <Card variant="bordered">
+          <p className="text-center text-gray-500">暂无文档</p>
+        </Card>
+      )}
+    </div>
+  );
+}