fix: knowledge base reset

src/lib/components/workspace/Knowledge/KnowledgeBase.svelte

@@ -68,7 +68,7 @@
 	let inputFiles = null;
 
 	let filteredItems = [];
-	$: if (knowledge) {
+	$: if (knowledge && knowledge.files) {
 		fuse = new Fuse(knowledge.files, {
 			keys: ['meta.name', 'meta.description']
 		});