slog: Add support for attaching stacktraces

[taiheserver]

Problem Statement

SentryHandler call CaptureEvent directly, but if want to AttachStacktrace, need to call CaptureMessage instead

Solution Brainstorm

func (h *SentryHandler) Handle(ctx context.Context, record slog.Record) error {
	hub := sentry.CurrentHub()
	if hubFromContext := sentry.GetHubFromContext(ctx); hubFromContext != nil {
		hub = hubFromContext
	} else if h.option.Hub != nil {
		hub = h.option.Hub
	}

	fromContext := contextExtractor(ctx, h.option.AttrFromContext)
	event := h.option.Converter(h.option.AddSource, h.option.ReplaceAttr, append(h.attrs, fromContext...), h.groups, &record, hub)
	hub.CaptureMessage(event)

	return nil
}