feat: complete Day 21-24 knowledge base features

- Day 21-22: fix CORS and file upload issues
- Day 23-24: implement @knowledge base search and conversation integration
- Backend: integrate Dify RAG into conversation system
- Frontend: load knowledge base list and @ reference feature

backend/check-documents.js

@@ -0,0 +1,64 @@
+// 查询文档状态脚本
+const { PrismaClient } = require('@prisma/client');
+
+const prisma = new PrismaClient();
+
+async function checkDocuments() {
+  try {
+    console.log('\n📋 查询最近上传的文档...\n');
+    
+    const docs = await prisma.document.findMany({
+      orderBy: { uploadedAt: 'desc' },
+      take: 10,
+      include: {
+        knowledgeBase: {
+          select: {
+            name: true,
+          }
+        }
+      }
+    });
+    
+    if (docs.length === 0) {
+      console.log('❌ 没有找到任何文档');
+      return;
+    }
+    
+    console.log(`找到 ${docs.length} 个文档：\n`);
+    
+    docs.forEach((doc, index) => {
+      const statusEmoji = {
+        'uploading': '📤',
+        'parsing': '🔄',
+        'indexing': '⚙️',
+        'completed': '✅',
+        'error': '❌'
+      }[doc.status] || '❓';
+      
+      console.log(`${index + 1}. ${statusEmoji} ${doc.filename}`);
+      console.log(`   知识库: ${doc.knowledgeBase.name}`);
+      console.log(`   状态: ${doc.status}`);
+      console.log(`   大小: ${(doc.fileSizeBytes / 1024).toFixed(2)} KB`);
+      console.log(`   上传时间: ${doc.uploadedAt}`);
+      
+      if (doc.status === 'completed') {
+        console.log(`   ✓ 段落数: ${doc.segmentsCount || 0}`);
+        console.log(`   ✓ Token数: ${doc.tokensCount || 0}`);
+      }
+      
+      if (doc.status === 'error' && doc.errorMessage) {
+        console.log(`   ✗ 错误: ${doc.errorMessage}`);
+      }
+      
+      console.log('');
+    });
+    
+  } catch (error) {
+    console.error('❌ 查询失败:', error.message);
+  } finally {
+    await prisma.$disconnect();
+  }
+}
+
+checkDocuments();
+