ci: Jenkins pipeline and tests for packaging/release tools

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

scripts/ci-run.sh

@@ -0,0 +1,15 @@
+#!/bin/sh
+# Run a command in a throwaway container that sees this workspace.
+# The Jenkins agent talks to the host Docker daemon (DooD), so -v "$PWD" would point at a host path that
+# doesn't exist; reuse the agent container's mounts when we are inside one.
+# Usage: sh scripts/ci-run.sh IMAGE COMMAND [ARGS...]
+set -eu
+image=$1
+shift
+if docker inspect "$(hostname)" >/dev/null 2>&1; then
+  set -- --volumes-from "$(hostname)" -w "$PWD" "$image" "$@"
+else
+  set -- -v "$PWD":/app -w /app "$image" "$@"
+fi
+exec docker run --rm -u "$(id -u):$(id -g)" -e HOME=/tmp \
+  -e GITEA_TOKEN -e GITEA_URL -e GITEA_REPO -e GIT_COMMIT "$@"