refac: user message delete

src/lib/components/chat/Chat.svelte

@@ -212,7 +212,14 @@
 		const _chatId = JSON.parse(JSON.stringify($chatId));
 		let _messageId = JSON.parse(JSON.stringify(message.id));
 
-		let messageChildrenIds = history.messages[_messageId].childrenIds;
+		let messageChildrenIds = [];
+		if (_messageId === null) {
+			messageChildrenIds = Object.keys(history.messages).filter(
+				(id) => history.messages[id].parentId === null
+			);
+		} else {
+			messageChildrenIds = history.messages[_messageId].childrenIds;
+		}
 
 		while (messageChildrenIds.length !== 0) {
 			_messageId = messageChildrenIds.at(-1);

src/lib/components/chat/Messages/UserMessage.svelte

@@ -347,7 +347,7 @@
 								</button>
 							</Tooltip>
 
-							{#if !isFirstMessage && !readOnly}
+							{#if !readOnly && siblings.length > 1}
 								<Tooltip content={$i18n.t('Delete')} placement="bottom">
 									<button
 										class="invisible group-hover:visible p-1 rounded-sm dark:hover:text-white hover:text-black transition"