fix(observabillity): add service_name tag to logs

internal/log/default.go

@@ -27,6 +27,8 @@ func (l *logHandler) Enabled(ctx context.Context, level slog.Level) bool {
 
 // Handle implements slog.Handler.
 func (l *logHandler) Handle(ctx context.Context, rec slog.Record) error {
+	rec.AddAttrs(slog.String("service_name", "spend-sparrow"))
+
 	if err := l.console.Handle(ctx, rec); err != nil {
 		return err
 	}