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-docs-api.ps1

@@ -0,0 +1,70 @@
+# 通过API查询文档状态
+Write-Host "`n📋 查询知识库和文档状态...`n" -ForegroundColor Green
+
+# 获取知识库列表
+try {
+    $response = Invoke-RestMethod -Uri "http://localhost:3001/api/v1/knowledge-bases" -Method GET
+    
+    if ($response.data.Count -eq 0) {
+        Write-Host "❌ 没有找到任何知识库" -ForegroundColor Red
+        exit
+    }
+    
+    Write-Host "找到 $($response.data.Count) 个知识库：`n" -ForegroundColor Cyan
+    
+    foreach ($kb in $response.data) {
+        Write-Host "📚 知识库: $($kb.name)" -ForegroundColor Yellow
+        Write-Host "   ID: $($kb.id)"
+        Write-Host "   描述: $($kb.description)"
+        Write-Host "   文件数: $($kb.fileCount)"
+        Write-Host "   创建时间: $($kb.createdAt)"
+        
+        # 获取该知识库的文档列表
+        try {
+            $docsResponse = Invoke-RestMethod -Uri "http://localhost:3001/api/v1/knowledge-bases/$($kb.id)/documents" -Method GET
+            
+            if ($docsResponse.data.Count -gt 0) {
+                Write-Host "`n   📄 文档列表：" -ForegroundColor Cyan
+                
+                foreach ($doc in $docsResponse.data) {
+                    $statusEmoji = switch ($doc.status) {
+                        "uploading" { "📤" }
+                        "parsing" { "🔄" }
+                        "indexing" { "⚙️" }
+                        "completed" { "✅" }
+                        "error" { "❌" }
+                        default { "❓" }
+                    }
+                    
+                    Write-Host "   $statusEmoji $($doc.filename)" -ForegroundColor White
+                    Write-Host "      状态: $($doc.status)"
+                    Write-Host "      大小: $([math]::Round($doc.fileSizeBytes / 1024, 2)) KB"
+                    Write-Host "      上传时间: $($doc.uploadedAt)"
+                    
+                    if ($doc.status -eq "completed") {
+                        Write-Host "      ✓ 段落数: $($doc.segmentsCount)" -ForegroundColor Green
+                        Write-Host "      ✓ Token数: $($doc.tokensCount)" -ForegroundColor Green
+                    }
+                    
+                    if ($doc.status -eq "error" -and $doc.errorMessage) {
+                        Write-Host "      ✗ 错误: $($doc.errorMessage)" -ForegroundColor Red
+                    }
+                    
+                    Write-Host ""
+                }
+            } else {
+                Write-Host "   （该知识库暂无文档）`n"
+            }
+            
+        } catch {
+            Write-Host "   ❌ 获取文档列表失败: $($_.Exception.Message)" -ForegroundColor Red
+        }
+        
+        Write-Host ("-" * 60)
+        Write-Host ""
+    }
+    
+} catch {
+    Write-Host "❌ 查询失败: $($_.Exception.Message)" -ForegroundColor Red
+}
+