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/internal/config/config.go

@@ -15,6 +15,7 @@ type Config struct {
 	TeacherBffURL     string
 	CoreEduServiceURL string
 	ContentServiceURL string
+	DataAnaServiceURL string
 	OTLPEndpoint      string
 	LogLevel          string
 	DevMode           bool
@@ -31,6 +32,7 @@ func Load() *Config {
 		TeacherBffURL:     getEnv("TEACHER_BFF_URL", "http://localhost:3003"),
 		CoreEduServiceURL: getEnv("CORE_EDU_SERVICE_URL", "http://localhost:3004"),
 		ContentServiceURL: getEnv("CONTENT_SERVICE_URL", "http://localhost:3005"),
+		DataAnaServiceURL: getEnv("DATA_ANA_SERVICE_URL", "http://localhost:3006"),
 		OTLPEndpoint:      getEnv("OTEL_EXPORTER_OTLP_ENDPOINT", "http://localhost:4318"),
 		LogLevel:          getEnv("LOG_LEVEL", "info"),
 		DevMode:           getEnvBool("DEV_MODE", false),