feat: add within network check for approve events

internal/handler/within_network.go

@@ -0,0 +1,12 @@
+package handler
+
+import "context"
+
+func (hc *HandlerContainer) checkWithinNetwork(ctx context.Context, contractAddress string, from string, to string) (bool, error) {
+	exists, err := hc.cache.ExistsNetwork(ctx, contractAddress, from, to)
+	if err != nil {
+		return false, err
+	}
+
+	return exists, nil
+}