feat(kit): establish sandbox build script

build-sbx.sh

@@ -0,0 +1,27 @@
+#!/usr/bin/env bash
+
+# Build and optionally configure a Docker sandbox interactively.
+
+set -o errexit
+set -o nounset
+set -o pipefail
+
+readonly KIT_PATH="$HOME/.sbx/kits/hypoport.ai"
+readonly TEMPLATE='127.0.0.1:62735/finmas.de/mux033/opencode-ops:latest'
+
+require_command() {
+    local command_name="$1"
+    local message="$2"
+
+    if ! command -v "$command_name" >/dev/null 2>&1; then
+        printf '%s\n' "$message" >&2
+        exit 1
+    fi
+}
+
+main() {
+    require_command sbx 'We cannot build a Docker sbx image because sbx does not seem to be installed.'
+    require_command jq 'We cannot list existing Docker sbx sandboxes because jq does not seem to be installed.'
+}
+
+main "$@"