feat: 实现更新活动数据集元数据的功能，添加错误处理和文件写入逻辑

src/lib/stores/dataset.ts

@@ -1,8 +1,33 @@
 import type { DatasetMeta, ImageMeta } from "$lib/types/meta";
-import { writable } from "svelte/store";
+import { join } from "@tauri-apps/api/path";
+import { writeTextFile } from "@tauri-apps/plugin-fs";
+import { get, writable } from "svelte/store";
 
 export const openedDatasetDir = writable<string | null>(null);
 
 export const activeDatasetMeta = writable<DatasetMeta | null>(null);
 
 export const activeDatasetImageMetas = writable<ImageMeta[]>([]);
+
+type DatasetMetaUpdater = Partial<DatasetMeta> | ((current: DatasetMeta) => DatasetMeta);
+
+export async function updateActiveDatasetMeta(updater: DatasetMetaUpdater): Promise<DatasetMeta> {
+	const datasetDir = get(openedDatasetDir);
+	if (!datasetDir) {
+		throw new Error("Cannot update dataset meta: openedDatasetDir is null");
+	}
+
+	const currentMeta = get(activeDatasetMeta);
+	if (!currentMeta) {
+		throw new Error("Cannot update dataset meta: activeDatasetMeta is null");
+	}
+
+	const nextMeta =
+		typeof updater === "function" ? updater(currentMeta) : { ...currentMeta, ...updater };
+
+	const metaPath = await join(datasetDir, "meta.json");
+	await writeTextFile(metaPath, JSON.stringify(nextMeta, null, 2));
+	activeDatasetMeta.set(nextMeta);
+
+	return nextMeta;
+}