* feat(sandbox): add gpu sandbox scheduling support
Allow sandbox creation to request GPU resources explicitly or infer them from GPU image names. This wires GPU intent through bootstrap, validates gateway support, and adds dedicated GPU E2E coverage for follow-up cluster testing.
Add OPENSHELL_SANDBOX_IMAGE_PULL_POLICY env/CLI flag that propagates
through Config -> SandboxClient -> pod spec generation. When set, the
policy is applied to both inline and pod-template sandbox containers.
Helm chart exposes server.sandboxImagePullPolicy (default empty = K8s
default behavior). cluster-deploy-fast sets it to Always so dev
clusters always pull fresh sandbox images.
* refactor(docker): rename server image to gateway
Rename Dockerfile.server to Dockerfile.gateway and update all image
references from openshell/server to openshell/gateway across Helm
charts, Kubernetes manifests, mise tasks, build/deploy scripts, CI
workflows, and documentation.
The underlying Rust binary (navigator-server) is unchanged -- this
rename only affects the Docker image name and Dockerfile.
* fix: catch remaining server->gateway references in docs and comments
Piotr Mlocek