word_search: include data for cross references

lib/models/word_search/word_search_xref_entry.dart

@@ -1,3 +1,5 @@
+import 'package:jadb/models/word_search/word_search_result.dart';
+
 /// A cross-reference entry from one word-result to another entry.
 class WordSearchXrefEntry {
   /// The ID of the entry that this entry cross-references to.
@@ -13,11 +15,15 @@ class WordSearchXrefEntry {
   /// database (and hence might be incorrect).
   final bool ambiguous;
 
+  /// The result of the cross-reference, may or may not be included in the query.
+  final WordSearchResult? xrefResult;
+
   const WordSearchXrefEntry({
     required this.entryId,
     required this.ambiguous,
     required this.baseWord,
     required this.furigana,
+    required this.xrefResult,
   });
 
   Map<String, dynamic> toJson() => {
@@ -25,6 +31,7 @@ class WordSearchXrefEntry {
     'ambiguous': ambiguous,
     'baseWord': baseWord,
     'furigana': furigana,
+    'xrefResult': xrefResult?.toJson(),
   };
 
   factory WordSearchXrefEntry.fromJson(Map<String, dynamic> json) =>
@@ -33,5 +40,6 @@ class WordSearchXrefEntry {
         ambiguous: json['ambiguous'] as bool,
         baseWord: json['baseWord'] as String,
         furigana: json['furigana'] as String?,
+        xrefResult: null,
       );
 }