Scaffold vault-plugin-secrets-arrstack engine

Mint dynamic arrproxy machine tokens via arrproxy's bearer-gated admin API
so Terraform-driven *arr onboarding can issue and revoke per-role tokens
non-interactively.

- Add backend, config, roles, creds paths and the arrstack_token secret
- Call POST/DELETE /api/admin/tokens with a vault:arrstack:<role> subject
- Enforce apps as a non-empty subset of sonarr/radarr/prowlarr
- Cap lease renewal at the arrproxy token's fixed expiry
- Add table-driven unit tests against a fake arrproxy admin server
- Add Makefile, nfpm packaging, and pre-commit/build/test/release pipelines

scripts/build-rpm.sh

@@ -0,0 +1,54 @@
+#!/usr/bin/env bash
+#
+# Package the (already built) plugin binary into RPMs with nfpm.
+# Builds one RPM per target server: Vault (/opt/vault-plugins) and
+# OpenBao (/opt/openbao-plugins). Both wrap the same binary.
+# Usage: scripts/build-rpm.sh [version]   (version defaults to $CI_COMMIT_TAG)
+#
+set -euo pipefail
+
+ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+cd "${ROOT_DIR}"
+
+VERSION="${1:-${CI_COMMIT_TAG:-0.0.0-dev}}"
+VERSION="${VERSION#v}" # strip a leading v
+BINARY="vault-plugin-secrets-arrstack"
+DIST="dist"
+
+if [ ! -f "${DIST}/${BINARY}" ]; then
+  echo "ERROR: ${DIST}/${BINARY} not found; run 'make build' first" >&2
+  exit 1
+fi
+
+# The plugin is registered in Vault/OpenBao by the sha256 of the binary, and
+# Puppet pins that same digest. Print it so the release log records it.
+SHA256="$(sha256sum "${DIST}/${BINARY}" | cut -d' ' -f1)"
+echo "PLUGIN_SHA256 ${BINARY} ${VERSION} ${SHA256}"
+
+# Fields shared across every flavour.
+export PACKAGE_VERSION="${VERSION}"
+export PACKAGE_RELEASE="1"
+export PACKAGE_ARCH="amd64"
+export PACKAGE_PLATFORM="linux"
+export PACKAGE_DESCRIPTION="Vault/OpenBao dynamic secrets engine for arrproxy machine tokens"
+export PACKAGE_MAINTAINER="Ben Vincent <ben@unkin.net>"
+export PACKAGE_HOMEPAGE="https://git.unkin.net/unkin/vault-plugin-secrets-arrstack"
+export PACKAGE_LICENSE="MIT"
+
+# build_flavor <package-name> <plugin-dir>
+build_flavor() {
+  export PACKAGE_NAME="$1"
+  export PACKAGE_PLUGIN_DIR="$2"
+  export PACKAGE_PREINSTALL="${DIST}/preinstall-${PACKAGE_NAME}.sh"
+
+  envsubst '${PACKAGE_PLUGIN_DIR}' \
+    < packaging/scripts/preinstall.sh.tmpl > "${PACKAGE_PREINSTALL}"
+  envsubst < packaging/nfpm.yaml > "${DIST}/nfpm-${PACKAGE_NAME}.yaml"
+  nfpm pkg --config "${DIST}/nfpm-${PACKAGE_NAME}.yaml" --target "${DIST}" --packager rpm
+}
+
+build_flavor "vault-plugin-secrets-arrstack"   "/opt/vault-plugins"
+build_flavor "openbao-plugin-secrets-arrstack" "/opt/openbao-plugins"
+
+echo "Built:"
+ls -1 "${DIST}"/*.rpm