fix: add --load to buildx to ensure images are available locally

When building v4 services with buildx, the resulting image may not
be found by Docker Compose because buildx only stores images in its
cache by default. Adding --load exports the build result into the
local Docker daemon.

Backport of lando/core#424

Author: AaronFeledy

CHANGELOG.md

@@ -1,5 +1,7 @@
 ## {{ UNRELEASED_VERSION }} - [{{ UNRELEASED_DATE }}]({{ UNRELEASED_LINK }})
 
+* Fixed `buildx` built images not being available locally by adding `--load` flag [lando/core#424](https://github.com/lando/core/pull/424)
+
 ## v4.0.0-unstable.8 - [December 9, 2025](https://github.com/lando/core-next/releases/tag/v4.0.0-unstable.8)
 
 * Updated to prep for `bunification` part 2

components/docker-engine.js

@@ -251,6 +251,7 @@ class DockerEngine extends Dockerode {
         'buildx',
         'build',
         `--file=${dockerfile}`,
+        '--load',
         '--progress=plain',
         `--tag=${tag}`,
         context,