Chat Prompt Suggestions: Support nested option path for suggestions updates (DevExpress#33312)

Co-authored-by: marker dao ® <youdontknow@marker-dao.eth>

Author: marker-dao

packages/devextreme/js/__internal/ui/chat/chat.ts

@@ -786,9 +786,11 @@ class Chat extends Widget<ChatProperties> {
         this._createSendButtonAction();
         this._messageBox.option(name, this._getSendButtonOptionsWithAction());
         break;
-      case 'suggestions':
-        this._suggestions?.updateOptions(value as ChatProperties['suggestions']);
+      case 'suggestions': {
+        const { suggestions } = this.option();
+        this._suggestions?.updateOptions(suggestions);
         break;
+      }
       default:
         super._optionChanged(args);
     }

packages/devextreme/testing/tests/DevExpress.ui.widgets/chatParts/chat.tests.js

@@ -2821,6 +2821,36 @@ QUnit.module('Chat', () => {
             assert.strictEqual(this.getSuggestionsElement().length, 1, 'suggestions container remains in DOM');
             assert.strictEqual(this.getSuggestionItems().length, 0, 'items are removed');
         });
+
+        QUnit.test('suggestions items should be updated via nested option path', function(assert) {
+            this.reinit({
+                suggestions: { items: [{ text: 'Item 1' }] },
+            });
+
+            this.instance.option('suggestions.items', [{ text: 'New 1' }, { text: 'New 2' }]);
+
+            assert.strictEqual(this.getSuggestionItems().length, 2, 'items count updated via nested path');
+            assert.strictEqual(this.getSuggestionItems().eq(0).text(), 'New 1', 'first item text updated');
+        });
+
+        QUnit.test('nested option update should not drop other suggestions options', function(assert) {
+            assert.expect(1);
+
+            const clickedText = 'Item 1';
+
+            this.reinit({
+                suggestions: {
+                    items: [{ text: clickedText }],
+                    onItemClick: (e) => {
+                        assert.strictEqual(e.itemData.text, clickedText, 'onItemClick preserved after nested update');
+                    },
+                },
+            });
+
+            this.instance.option('suggestions.items', [{ text: clickedText }, { text: 'Item 2' }]);
+
+            this.getSuggestionItems().first().trigger('dxclick');
+        });
     });
 
     QUnit.module('Data Layer Integration', {