Fix errors for RangeErrors, Fix for accessing undefined objects in Chat.svelte

src/lib/components/chat/Chat.svelte

@@ -839,13 +839,15 @@
 		if (res !== null && res.messages) {
 			// Update chat history with the new messages
 			for (const message of res.messages) {
-				history.messages[message.id] = {
-					...history.messages[message.id],
-					...(history.messages[message.id].content !== message.content
-						? { originalContent: history.messages[message.id].content }
-						: {}),
-					...message
-				};
+				if (message && message.id) {  // Add null check for message and message.id
+					history.messages[message.id] = {
+						...history.messages[message.id],
+						...(history.messages[message.id].content !== message.content
+							? { originalContent: history.messages[message.id].content }
+							: {}),
+						...message
+					};
+				}
 			}
 		}
 
@@ -1348,7 +1350,7 @@
 				history.currentId = responseMessageId;
 
 				// Append messageId to childrenIds of parent message
-				if (parentId !== null) {
+				if (parentId !== null && history.messages[parentId]) { // Add null check before accessing childrenIds
 					history.messages[parentId].childrenIds = [
 						...history.messages[parentId].childrenIds,
 						responseMessageId
@@ -1526,7 +1528,7 @@
 							: undefined
 				},
 
-				files: files.length > 0 ? files : undefined,
+				files: (files?.length ?? 0) > 0 ? files : undefined,
 				tool_ids: selectedToolIds.length > 0 ? selectedToolIds : undefined,
 				features: {
 					web_search: webSearchEnabled