feat(fingerprint): integrate htmlHash into DqElement toJSON

Compute htmlHash from element.outerHTML before truncation.
Added to toJSON() output alongside selector, source, xpath, etc.
Handles null element (spec/virtualNode) case gracefully.

Author: Abhishek Bindra

lib/core/utils/dq-element.js

@@ -7,6 +7,7 @@ import cache from '../base/cache';
 import memoize from './memoize';
 import getNodeAttributes from './get-node-attributes';
 import VirtualNode from '../../core/base/virtual-node/virtual-node';
+import computeFingerprintHash from './fingerprint';
 
 const CACHE_KEY = 'DqElm.RunOptions';
 
@@ -341,6 +342,15 @@ const DqElement = memoize(function DqElement(elm, options, spec) {
     this.nodeIndexes = [this._virtualNode.nodeIndex];
   }
 
+  // [a11y-core]: compute htmlHash before truncation
+  try {
+    this._htmlHash = this._element
+      ? computeFingerprintHash(this._element.outerHTML)
+      : null;
+  } catch {
+    this._htmlHash = null;
+  }
+
   /**
    * The generated HTML source code of the element
    * @type {String|null}
@@ -411,7 +421,8 @@ DqElement.prototype = {
       xpath: this.xpath,
       ancestry: this.ancestry,
       nodeIndexes: this.nodeIndexes,
-      fromFrame: this.fromFrame
+      fromFrame: this.fromFrame,
+      htmlHash: this._htmlHash
     };
     if (this._includeElementInJson) {
       spec.element = this._element;