safer mempool cloning for different GBT algorithms

backend/src/utils/clone.ts

@@ -0,0 +1,14 @@
+// simple recursive deep clone for literal-type objects
+// does not preserve Dates, Maps, Sets etc
+// does not support recursive objects
+// properties deeper than maxDepth will be shallow cloned
+export function deepClone(obj: any, maxDepth: number = 50, depth: number = 0): any {
+  let cloned = obj;
+  if (depth < maxDepth && typeof obj === 'object') {
+    cloned = Array.isArray(obj) ? [] : {};
+    for (const key in obj) {
+      cloned[key] = deepClone(obj[key], maxDepth, depth + 1);
+    }
+  }
+  return cloned;
+}