docs(config): document Alpine default images

Signed-off-by: Evan Lezar <elezar@nvidia.com>

deploy/helm/openshell/README.md

@@ -289,7 +289,7 @@ discovery endpoint or its TLS CA.
 | server.policyValidationFailureMode | string | `"fail_closed"` | Posture when a candidate sandbox policy fails validation. `fail_closed` deactivates the previous policy; `retain_last_valid` keeps it active. |
 | server.providerTokenGrants.spiffe.enabled | bool | `false` | Mount the SPIFFE Workload API socket into gateway and sandbox pods for dynamic provider token grants. |
 | server.providerTokenGrants.spiffe.workloadApiSocketPath | string | `"/spiffe-workload-api/spire-agent.sock"` | Path to the SPIFFE Workload API socket mounted into gateway and sandbox pods. |
-| server.sandboxImage | string | `"ghcr.io/nvidia/openshell-community/sandboxes/base:latest"` | Default sandbox image used when requests do not specify one. |
+| server.sandboxImage | string | `"docker.io/library/alpine:3.22"` | Default sandbox image used when requests do not specify one. |
 | server.sandboxImagePullPolicy | string | `nil` | Pull policy for sandbox pods. Leave unset to use the Kubernetes image default (Always for :latest, IfNotPresent otherwise). Prefer always, if_not_present, or never; the chart also accepts legacy Kubernetes spellings Always, IfNotPresent, and Never. |
 | server.sandboxImagePullSecrets | list | `[]` | Image pull secrets attached to sandbox pods. Referenced Secrets must exist in the sandbox namespace. |
 | server.sandboxJwt.gatewayId | string | `""` | Stable gateway identity embedded in iss/aud of every minted token. Defaults to the release name so HA replicas share identity. |

docs/reference/gateway-config.mdx

@@ -246,7 +246,7 @@ phases = ["validate"]
 namespace              = "openshell"
 # Required in raw TOML; Helm derives this from the gateway Service.
 grpc_endpoint          = "https://openshell-gateway.openshell.svc:8080"
-default_image          = "ghcr.io/nvidia/openshell/sandbox:latest"
+default_image          = "docker.io/library/alpine:3.22"
 # Defaults to the gateway version; override to pin a specific build.
 # supervisor_image     = "ghcr.io/nvidia/openshell/supervisor:<version>"
 client_tls_secret_name = "openshell-client-tls"
@@ -549,7 +549,7 @@ workspace_mode                 = "shared"
 # gateway_id                   = "openshell"
 namespace                      = "agents"
 service_account_name           = "openshell-sandbox"
-default_image                  = "ghcr.io/nvidia/openshell-community/sandboxes/base:latest"
+default_image                  = "docker.io/library/alpine:3.22"
 image_pull_policy              = "if_not_present"
 image_pull_secrets             = ["regcred"]
 # Defaults to the gateway version; override to pin a specific build.
@@ -699,7 +699,7 @@ guest_tls_key  = "/etc/openshell/certs/client-key.pem"
 
 [openshell.drivers.docker]
 socket_path        = "/var/run/docker.sock"
-default_image      = "ghcr.io/nvidia/openshell-community/sandboxes/base:latest"
+default_image      = "docker.io/library/alpine:3.22"
 # Canonical values: always | if_not_present | never. `newer` is Podman-only.
 image_pull_policy  = "if_not_present"
 # Value assigned to the openshell.sandbox_namespace label on sandbox containers.
@@ -759,7 +759,7 @@ network_name            = "openshell"
 # asks the podman CLI where its socket is, and fails to start if neither finds
 # one. Set this to pin a specific Podman machine instead.
 socket_path             = "/run/user/1000/podman/podman.sock"
-default_image           = "ghcr.io/nvidia/openshell-community/sandboxes/base:latest"
+default_image           = "docker.io/library/alpine:3.22"
 image_pull_policy       = "if_not_present" # always | if_not_present | never | newer
 # Optional override. When omitted, Linux uses gateway loopback and Podman
 # Machine uses host.containers.internal.