network: add auto-detection of optimal MTU for WireGuard interface, --wg-mtu flag, set max_mtu for Corrosion to 1232

internal/machine/docker/controller_darwin.go

@@ -9,7 +9,9 @@ import (
 )
 
 // EnsureUncloudNetwork is a stub for Darwin.
-func (c *Controller) EnsureUncloudNetwork(ctx context.Context, subnet netip.Prefix, dnsServer netip.Addr) error {
+func (c *Controller) EnsureUncloudNetwork(
+	ctx context.Context, subnet netip.Prefix, mtu int, dnsServer netip.Addr,
+) error {
 	return fmt.Errorf("not supported on Darwin")
 }