feat: 基本的websocket echo服务

interval/api/handler/health.go

@@ -4,5 +4,7 @@ import "net/http"
 
 func Health(w http.ResponseWriter, _ *http.Request) {
 	w.WriteHeader(http.StatusOK)
-	w.Write([]byte("OK"))
+	if _, err := w.Write([]byte("OK")); err != nil {
+		http.Error(w, "failed to write response", http.StatusInternalServerError)
+	}
 }