feat(sync): full code sync from release

backend/internal/service/ops_upstream_context.go

@@ -27,6 +27,11 @@ const (
 	OpsUpstreamLatencyMsKey  = "ops_upstream_latency_ms"
 	OpsResponseLatencyMsKey  = "ops_response_latency_ms"
 	OpsTimeToFirstTokenMsKey = "ops_time_to_first_token_ms"
+	// OpenAI WS 关键观测字段
+	OpsOpenAIWSQueueWaitMsKey = "ops_openai_ws_queue_wait_ms"
+	OpsOpenAIWSConnPickMsKey  = "ops_openai_ws_conn_pick_ms"
+	OpsOpenAIWSConnReusedKey  = "ops_openai_ws_conn_reused"
+	OpsOpenAIWSConnIDKey      = "ops_openai_ws_conn_id"
 
 	// OpsSkipPassthroughKey 由 applyErrorPassthroughRule 在命中 skip_monitoring=true 的规则时设置。
 	// ops_error_logger 中间件检查此 key，为 true 时跳过错误记录。