refactor: improve task management with xsync for concurrent access and enhance callback and subtasks handling as well as memory allocation

internal/metrics/period/poller.go

@@ -134,7 +134,7 @@ func (p *Poller[T, AggregateT]) pollWithTimeout(ctx context.Context) {
 }
 
 func (p *Poller[T, AggregateT]) Start() {
-	t := task.RootTask("poller." + p.name)
+	t := task.RootTask("poller."+p.name, true)
 	l := log.With().Str("name", p.name).Logger()
 	err := p.load()
 	if err != nil {