Fix Blank Node handling

Author: M-Jafarkhani

meta_configurator/src/components/panels/rdf/rdf-authoring/RdfTripleDetailHelpDialog.vue

@@ -8,13 +8,21 @@
     <div class="flex flex-col gap-3 text-sm">
       <ul class="pl-4 list-disc leading-relaxed">
         <li>
-          Choosing <code>Blank Node</code> for subject or object always creates a new internal blank
-          node at root level on save.
+          Choosing <code>Blank Node</code> for a new subject or object creates a new internal blank
+          node on save.
+        </li>
+        <li>
+          When you edit an existing triple that already references a blank node, the blank node id
+          is preserved instead of creating a new one.
         </li>
         <li>
           Existing blank nodes are not listed in subject/object dropdowns. Those lists contain only
           named node IRIs.
         </li>
+        <li>
+          Tracking active selection between RDF View and Text View is currently not working for
+          triples containing blank nodes.
+        </li>
         <li>Blank nodes do not support IRI-based rename.</li>
       </ul>
       <Divider align="left" type="dashed">

meta_configurator/src/components/panels/rdf/tripleEditorService.ts

@@ -91,7 +91,7 @@ function createNode(
     case RdfTermType.NamedNode:
       return $rdf.sym(value);
     case RdfTermType.BlankNode:
-      return $rdf.blankNode();
+      return $rdf.blankNode(normalizeBlankNodeId(value));
     case RdfTermType.Literal:
       return datatype
         ? $rdf.literal(value, $rdf.sym(expandDatatype(datatype)))
@@ -100,3 +100,8 @@ function createNode(
       throw new Error(`Unknown term type: ${type}`);
   }
 }
+
+function normalizeBlankNodeId(value: string): string | undefined {
+  if (!value) return undefined;
+  return value.startsWith('_:') ? value.slice(2) : value;
+}