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/install/install.go

@@ -44,6 +44,7 @@ func Ensure() error {
 	}
 
 	hadStartup := startup.Enabled()
+	hadWatchdog := startup.WatchdogEnabled()
 	takeover(target)
 	if err := replaceExe(current, target); err != nil {
 		return fmt.Errorf("copy to %s: %w", target, err)
@@ -53,6 +54,11 @@ func Ensure() error {
 			helpers.Log.Printf("takeover: restore startup: %v", err)
 		}
 	}
+	if hadWatchdog {
+		if err := startup.EnableWatchdog(); err != nil {
+			helpers.Log.Printf("takeover: restore watchdog: %v", err)
+		}
+	}
 
 	return relaunchInstalled(target)
 }
@@ -62,6 +68,9 @@ func takeover(installed string) {
 	if err := startup.Disable(); err != nil {
 		helpers.Log.Printf("takeover: disable old startup: %v", err)
 	}
+	if err := startup.DisableWatchdog(); err != nil {
+		helpers.Log.Printf("takeover: disable old watchdog: %v", err)
+	}
 	if err := instance.KillOtherAgents(); err != nil {
 		helpers.Log.Printf("takeover: kill: %v", err)
 	}