feat(data-ana): 完善学情诊断服务并添加ClickHouse降级模式

config.py ClickHouse连接改可选+加DEV_MODE/kafka_brokers

clickhouse_client.py 降级模式: host为空时返回None

main.py 端点先查ClickHouse降级返回骨架数据+新增errorbook

新增clickhouse-init.sql创建宽表和错题表

Gateway添加/analytics路由

services/api-gateway/main.go

@@ -108,6 +108,15 @@ func main() {
 		api.Any("/knowledge-points/*path", contentHandler)
 		api.Any("/questions", contentHandler)
 		api.Any("/questions/*path", contentHandler)
+
+		// data-ana 服务路由（学情诊断/错题本）
+		dataAnaProxy, err := proxy.NewProxy(cfg.DataAnaServiceURL)
+		if err != nil {
+			log.Fatalf("failed to create data-ana proxy: %v", err)
+		}
+		dataAnaHandler := proxy.ProxyHandler(dataAnaProxy)
+		api.Any("/analytics", dataAnaHandler)
+		api.Any("/analytics/*path", dataAnaHandler)
 	}
 
 	srv := &http.Server{