feat(update-center): 实现集中式软件更新中心功能

新增更新中心模块，支持管理 APM 和传统 deb 软件更新任务
- 添加更新任务队列管理、状态跟踪和日志记录功能
- 实现更新项忽略配置持久化存储
- 新增更新确认对话框和迁移提示
- 优化主窗口关闭时的任务保护机制
- 添加单元测试覆盖核心逻辑

electron/main/backend/update-center/download.ts

@@ -0,0 +1,87 @@
+import { mkdir } from "node:fs/promises";
+import { join } from "node:path";
+import { spawn } from "node:child_process";
+
+import type { UpdateCenterItem } from "./types";
+
+export interface Aria2DownloadResult {
+  filePath: string;
+}
+
+export interface RunAria2DownloadOptions {
+  item: UpdateCenterItem;
+  downloadDir: string;
+  onProgress?: (progress: number) => void;
+  onLog?: (message: string) => void;
+  signal?: AbortSignal;
+}
+
+const PROGRESS_PATTERN = /(\d{1,3}(?:\.\d+)?)%/;
+
+export const runAria2Download = async ({
+  item,
+  downloadDir,
+  onProgress,
+  onLog,
+  signal,
+}: RunAria2DownloadOptions): Promise<Aria2DownloadResult> => {
+  if (!item.downloadUrl || !item.fileName) {
+    throw new Error(`Missing download metadata for ${item.pkgname}`);
+  }
+
+  await mkdir(downloadDir, { recursive: true });
+
+  const filePath = join(downloadDir, item.fileName);
+
+  await new Promise<void>((resolve, reject) => {
+    const child = spawn("aria2c", [
+      "--dir",
+      downloadDir,
+      "--out",
+      item.fileName,
+      item.downloadUrl,
+    ]);
+
+    const abortDownload = () => {
+      child.kill();
+      reject(new Error(`Update task cancelled: ${item.pkgname}`));
+    };
+
+    if (signal?.aborted) {
+      abortDownload();
+      return;
+    }
+
+    signal?.addEventListener("abort", abortDownload, { once: true });
+
+    const handleOutput = (chunk: Buffer) => {
+      const message = chunk.toString().trim();
+      if (!message) {
+        return;
+      }
+
+      onLog?.(message);
+      const progressMatch = message.match(PROGRESS_PATTERN);
+      if (progressMatch) {
+        onProgress?.(Number(progressMatch[1]));
+      }
+    };
+
+    child.stdout?.on("data", handleOutput);
+    child.stderr?.on("data", handleOutput);
+    child.on("error", reject);
+    child.on("close", (code) => {
+      signal?.removeEventListener("abort", abortDownload);
+      if (code === 0) {
+        resolve();
+        return;
+      }
+
+      reject(new Error(`aria2c exited with code ${code ?? -1}`));
+    });
+  });
+
+  onProgress?.(100);
+
+  return { filePath };
+};