feat: add backend handling for unarchiving all chats

The previous implementation for unarchiving all chats in `ArchivedChatsModal.svelte` was inefficient, as it sent a separate request for each chat, which could potentially overload the server.

This commit introduces a new backend endpoint, `/chats/unarchive/all`, to handle the bulk unarchiving of all chats for a user with a single API call.

The frontend has been updated to use this new endpoint, resolving the performance issue by minimizing the number of requests to the server.

src/lib/apis/chats/index.ts

@@ -33,6 +33,38 @@ export const createNewChat = async (token: string, chat: object, folderId: strin
 	return res;
 };
 
+export const unarchiveAllChats = async (token: string) => {
+	let error = null;
+
+	const res = await fetch(`${WEBUI_API_BASE_URL}/chats/unarchive/all`, {
+		method: 'POST',
+		headers: {
+			Accept: 'application/json',
+			'Content-Type': 'application/json',
+			...(token && { authorization: `Bearer ${token}` })
+		}
+	})
+		.then(async (res) => {
+			if (!res.ok) throw await res.json();
+			return res.json();
+		})
+		.then((json) => {
+			return json;
+		})
+		.catch((err) => {
+			error = err.detail;
+
+			console.error(err);
+			return null;
+		});
+
+	if (error) {
+		throw error;
+	}
+
+	return res;
+};
+
 export const importChat = async (
 	token: string,
 	chat: object,