Share host image store with nested podman in tests

Mount the host's podman graph root as a read-only additional
image store inside the nested container. The inner podman sees
all host images instantly without network pulls.

Assisted-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: alicefr

hack/test-container-image.sh

@@ -38,13 +38,25 @@ run_test() {
             ;;
         nested)
             nested_container="bink-nested-${cluster_name}"
+            HOST_GRAPH_ROOT=$(podman info --format '{{.Store.GraphRoot}}')
+            storage_conf=$(mktemp)
+            cat > "${storage_conf}" <<'STOREOF'
+[storage]
+driver = "overlay"
+[storage.options]
+additionalimagestores = ["/host-store"]
+STOREOF
             echo "Starting bink daemon container: ${nested_container}"
+            echo "  Sharing host image store from ${HOST_GRAPH_ROOT}"
             podman run -d --name "${nested_container}" --privileged \
                 --device /dev/kvm \
                 --ulimit core=-1:-1 \
                 -v "bink-test-storage:/var/lib/containers" \
+                -v "${HOST_GRAPH_ROOT}:/host-store:ro" \
+                -v "${storage_conf}:/etc/containers/storage.conf:ro" \
                 -v "$(pwd):/output" \
                 "${BINK_IMAGE}"
+            rm -f "${storage_conf}"
             echo "Waiting for podman service inside container..."
             for _ in $(seq 1 30); do
                 if podman exec "${nested_container}" podman info &>/dev/null; then
@@ -56,6 +68,8 @@ run_test() {
             # unreachable from inside nested podman networks. Override it so inner aardvark-dns
             # forwards queries to a public resolver instead.
             podman exec "${nested_container}" bash -c 'echo "nameserver 8.8.8.8" > /etc/resolv.conf'
+            echo "Images available in nested podman:"
+            podman exec "${nested_container}" podman images --format "table {{.Repository}}:{{.Tag}}\t{{.Size}}"
             bink_args=(podman exec "${nested_container}" bink)
             ;;
         *)