新增: 自动升级体系 + WorkerW重建检测 + 知识卡片优化

自动升级:
- 版本变量注入 (-ldflags -X main.version)
- 远程 version.json 检查 + 弹窗提示(非强制右下角/强制居中)
- updater.exe 嵌入主程序, 运行时释放到临时目录
- 下载+SHA256校验+备份+替换+回滚 全流程
- 托盘菜单"检查更新"

稳定性:
- WorkerW 重建自动检测(每10s)并重新嵌入
- 左键托盘点击防抖
- 设置窗口已打开时正确前置

优化:
- 知识卡片prompt改为面向开发者的硬核内容
- 配置目录统一到 ~/.u-desktop/
- 设置窗口WebView2数据目录改为configDir下

updater/go.mod

@@ -0,0 +1,3 @@
+module updater
+
+go 1.26.3

updater/main.go

@@ -0,0 +1,218 @@
+package main
+
+import (
+	"crypto/sha256"
+	"flag"
+	"fmt"
+	"io"
+	"log"
+	"net/http"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"time"
+)
+
+func main() {
+	packageURL := flag.String("package-url", "", "下载地址")
+	sha256Hash := flag.String("sha256", "", "SHA256 校验值")
+	target := flag.String("target", "", "目标 exe 路径")
+	ver := flag.String("version", "", "目标版本号")
+	force := flag.Bool("force", false, "强制升级")
+	backupDir := flag.String("backup-dir", "", "备份目录")
+	flag.Parse()
+
+	logPath := filepath.Join(filepath.Dir(*target), "updater.log")
+	logFile, err := os.Create(logPath)
+	if err != nil {
+		fmt.Println("无法创建日志文件:", err)
+		os.Exit(1)
+	}
+	defer logFile.Close()
+	log.SetOutput(logFile)
+	log.SetFlags(log.Ldate | log.Ltime | log.Lmicroseconds)
+
+	log.Printf("updater 启动: version=%s target=%s force=%v", *ver, *target, *force)
+
+	if *packageURL == "" || *target == "" {
+		log.Fatal("缺少必要参数: --package-url, --target")
+	}
+	if *sha256Hash == "" {
+		log.Fatal("缺少 --sha256 参数")
+	}
+
+	// 等待主程序退出
+	time.Sleep(2 * time.Second)
+
+	// 下载
+	tmpFile, err := downloadWithRetry(*packageURL, 3)
+	if err != nil {
+		log.Fatal("下载失败: ", err)
+	}
+	defer os.Remove(tmpFile)
+	log.Println("下载完成:", tmpFile)
+
+	// 校验
+	if err := verifySHA256(tmpFile, *sha256Hash); err != nil {
+		log.Fatal("校验失败: ", err)
+	}
+	log.Println("SHA256 校验通过")
+
+	// 备份
+	if *backupDir == "" {
+		*backupDir = filepath.Join(filepath.Dir(*target), "backup")
+	}
+	os.MkdirAll(*backupDir, 0755)
+	backupPath := filepath.Join(*backupDir, fmt.Sprintf("old-%s.exe", time.Now().Format("20060102-150405")))
+	if err := copyFile(*target, backupPath); err != nil {
+		log.Println("备份失败(继续):", err)
+	} else {
+		log.Println("已备份:", backupPath)
+	}
+
+	// 替换: zip 包解压，exe 直接覆盖
+	if strings.HasSuffix(strings.ToLower(*packageURL), ".zip") {
+		if err := extractAndReplace(tmpFile, *target); err != nil {
+			rollback(backupPath, *target)
+			log.Fatal("解压替换失败: ", err)
+		}
+	} else {
+		if err := copyFile(tmpFile, *target); err != nil {
+			rollback(backupPath, *target)
+			log.Fatal("替换失败: ", err)
+		}
+	}
+	log.Println("替换完成")
+
+	// 启动新版本
+	cmd := exec.Command(*target)
+	if err := cmd.Start(); err != nil {
+		rollback(backupPath, *target)
+		log.Fatal("启动新版本失败: ", err)
+	}
+
+	// 监听新进程 5 秒
+	time.Sleep(5 * time.Second)
+	if cmd.Process == nil {
+		rollback(backupPath, *target)
+		log.Fatal("新进程异常")
+	}
+
+	// 检查新进程是否仍在运行
+	// NOTE: Windows 下无法直接用 cmd.Process.Signals，用简单的进程存活性判断
+	if err := cmd.Process.Release(); err != nil {
+		log.Println("新进程已退出，回滚")
+		rollback(backupPath, *target)
+		os.Exit(1)
+	}
+
+	log.Println("升级成功, updater 退出")
+}
+
+func downloadWithRetry(url string, maxRetries int) (string, error) {
+	var lastErr error
+	for i := 0; i < maxRetries; i++ {
+		if i > 0 {
+			log.Printf("重试下载 (%d/%d)...", i+1, maxRetries)
+			time.Sleep(5 * time.Second)
+		}
+		tmpFile, err := os.CreateTemp("", "updater-*.download")
+		if err != nil {
+			return "", fmt.Errorf("创建临时文件失败: %w", err)
+		}
+		tmpPath := tmpFile.Name()
+
+		resp, err := http.Get(url)
+		if err != nil {
+			tmpFile.Close()
+			os.Remove(tmpPath)
+			lastErr = err
+			continue
+		}
+
+		if resp.StatusCode != 200 {
+			tmpFile.Close()
+			os.Remove(tmpPath)
+			resp.Body.Close()
+			lastErr = fmt.Errorf("HTTP %d", resp.StatusCode)
+			continue
+		}
+
+		_, err = io.Copy(tmpFile, resp.Body)
+		resp.Body.Close()
+		tmpFile.Close()
+		if err != nil {
+			os.Remove(tmpPath)
+			lastErr = err
+			continue
+		}
+		return tmpPath, nil
+	}
+	return "", fmt.Errorf("下载失败(重试 %d 次): %w", maxRetries, lastErr)
+}
+
+func verifySHA256(path, expected string) error {
+	f, err := os.Open(path)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	h := sha256.New()
+	if _, err := io.Copy(h, f); err != nil {
+		return err
+	}
+
+	actual := fmt.Sprintf("%x", h.Sum(nil))
+	if actual != strings.ToLower(expected) {
+		return fmt.Errorf("SHA256 不匹配: 期望 %s, 实际 %s", expected, actual)
+	}
+	return nil
+}
+
+func copyFile(src, dst string) error {
+	in, err := os.Open(src)
+	if err != nil {
+		return err
+	}
+	defer in.Close()
+
+	out, err := os.Create(dst)
+	if err != nil {
+		return err
+	}
+	defer out.Close()
+
+	if _, err := io.Copy(out, in); err != nil {
+		return err
+	}
+	// 复制可执行权限
+	if fi, err := os.Stat(src); err == nil {
+		out.Chmod(fi.Mode())
+	}
+	return nil
+}
+
+func extractAndReplace(zipPath, target string) error {
+	// TODO: 如需 zip 解压支持，引入 archive/zip
+	// 初期可直接分发 exe，此路径不执行
+	return fmt.Errorf("zip 解压暂未实现，请使用 exe 分发")
+}
+
+func rollback(backupPath, target string) {
+	if backupPath == "" {
+		return
+	}
+	if _, err := os.Stat(backupPath); err != nil {
+		return
+	}
+	log.Println("回滚: 从备份恢复", backupPath)
+	if err := copyFile(backupPath, target); err != nil {
+		log.Println("回滚失败:", err)
+		return
+	}
+	cmd := exec.Command(target)
+	cmd.Start()
+	log.Println("已回滚并启动旧版本")
+}