fix: correct event handler registration in plugins

Fixed incorrect event handler registration in two plugins:

- Statistics plugin was calling Step instead of Stop on StopEvent,
  preventing statistics from being printed at the end of execution.
- Logs plugin was listening to StopEvent instead of StepEvent,
  causing it to only log once at the end instead of on each step.

internal/plugins/debug.go

@@ -14,7 +14,7 @@ type Logs struct {
 
 func NewLogs(logger *slog.Logger, process *engine.Engine) *Logs {
 	plugin := &Logs{logger, process}
-	process.On(engine.StopEvent, plugin.Step)
+	process.On(engine.StepEvent, plugin.Step)
 
 	return plugin
 }

internal/plugins/statistics.go

@@ -20,7 +20,7 @@ func NewStatistics(process *engine.Engine) *Statistics {
 	plugin := &Statistics{}
 	process.On(engine.StartEvent, plugin.Start)
 	process.On(engine.StepEvent, plugin.Step)
-	process.On(engine.StopEvent, plugin.Step)
+	process.On(engine.StopEvent, plugin.Stop)
 
 	return plugin
 }