ci: speed up backend build and parallelize image publishing [CI]

ci/publish-dev-node-indexes.sh

@@ -0,0 +1,31 @@
+#!/usr/bin/env bash
+# Publish Agent and Probe multi-architecture indexes concurrently in one CI step.
+set -euo pipefail
+
+root="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+publish_pids=()
+
+cancel_publishers() {
+  local pid
+  trap - TERM INT HUP
+  for pid in "${publish_pids[@]}"; do
+    kill -TERM "$pid" 2>/dev/null || true
+  done
+  for pid in "${publish_pids[@]}"; do
+    wait "$pid" 2>/dev/null || true
+  done
+  exit 143
+}
+trap cancel_publishers TERM INT HUP
+
+for component in agent probe; do
+  python3 "$root/ci/run-with-timeout.py" 900 \
+    bash "$root/ci/publish-dev-node-index.sh" "$component" &
+  publish_pids+=("$!")
+done
+
+publish_status=0
+for pid in "${publish_pids[@]}"; do
+  wait "$pid" || publish_status=1
+done
+exit "$publish_status"