feat(watchdog): separate watchdog from startup

- Add /api/v1/watchdog to enable/disable
- Scheduled task now runs every 15 minutes
- Use schtasks command line instead of XML
- Dashboard shows watchdog enabled state
- Preserve watchdog state during install

lib/startup/startup.go

@@ -33,36 +33,38 @@ func Enable() error {
 	if err := k.SetStringValue(config.StartupValueName, command); err != nil {
 		return err
 	}
-	return enableWatchdog()
+	return nil
 }
 
-// SyncInstalledPath rewrites an existing Run entry to the AppData install path.
+// SyncInstalledPath rewrites existing Run/watchdog entries to the AppData path.
 func SyncInstalledPath() error {
-	if !Enabled() {
-		return nil
+	if Enabled() {
+		if err := Enable(); err != nil {
+			return err
+		}
 	}
-	return Enable()
+	if WatchdogEnabled() {
+		if err := EnableWatchdog(); err != nil {
+			return err
+		}
+	}
+	return nil
 }
 
 func Disable() error {
-	var regErr error
 	k, err := registry.OpenKey(registry.CURRENT_USER, config.StartupRunKey, registry.SET_VALUE)
 	if err != nil {
-		if !errors.Is(err, registry.ErrNotExist) {
-			regErr = err
-		}
-	} else {
-		err = k.DeleteValue(config.StartupValueName)
-		_ = k.Close()
-		if err != nil && !errors.Is(err, registry.ErrNotExist) {
-			regErr = err
+		if errors.Is(err, registry.ErrNotExist) {
+			return nil
 		}
+		return err
 	}
-	taskErr := disableWatchdog()
-	if regErr != nil {
-		return regErr
+	defer k.Close()
+	err = k.DeleteValue(config.StartupValueName)
+	if errors.Is(err, registry.ErrNotExist) {
+		return nil
 	}
-	return taskErr
+	return err
 }
 
 func installedCommandLine() (string, error) {