feat(risk-control): add content moderation audit

backend/internal/handler/gemini_v1beta_handler.go

@@ -185,6 +185,11 @@ func (h *GatewayHandler) GeminiV1BetaModels(c *gin.Context) {
 	setOpsRequestContext(c, modelName, stream, body)
 	setOpsEndpointContext(c, "", int16(service.RequestTypeFromLegacy(stream, false)))
 
+	if decision := h.checkContentModeration(c, reqLog, apiKey, authSubject, service.ContentModerationProtocolGemini, modelName, body); decision != nil && decision.Blocked {
+		googleError(c, contentModerationStatus(decision), decision.Message)
+		return
+	}
+
 	// 解析渠道级模型映射
 	channelMapping, _ := h.gatewayService.ResolveChannelMappingAndRestrict(c.Request.Context(), apiKey.GroupID, modelName)
 	reqModel := modelName // 保存映射前的原始模型名