feat: signed releases and a host-side updater for container nodes

CI signs the image digest of each agent and probe release; the panel only
stores and forwards it. Nodes write the manifest to their data directory and
a host updater verifies the signature with a local public key, pulls by
digest, restarts the unit and rolls back when it is unhealthy. The panel can
list releases, ask a node to update and show the reported update state.

ci/build-main-amd64.sh

@@ -68,7 +68,7 @@ done
 for tag in latest "$dev_tag"; do
   pushed=false
   for attempt in 1 2 3; do
-    if buildah push --tls-verify=true "$local_image" "docker://$repository:$tag"; then
+    if buildah push --tls-verify=true --digestfile "$work/$component.digest" "$local_image" "docker://$repository:$tag"; then
       pushed=true
       break
     fi
@@ -80,3 +80,15 @@ for tag in latest "$dev_tag"; do
   [[ "$pushed" == true ]] || { echo "could not push $repository:$tag after 3 attempts" >&2; exit 1; }
   echo "pushed development image $repository:$tag"
 done
+
+# 发布清单：给镜像的 digest 签名（私钥只在 CI 密钥里），再登记到面板；面板把它原样转给在线的节点，节点宿主机上的更新器用本机的公钥验签后才会更新。
+# 没有配置签名密钥（例如 fork）就只构建镜像、不发清单。
+if [[ -n "${RELEASE_SIGNING_KEY:-}" ]]; then
+  digest="$(cat "$work/$component.digest")"
+  release_dir="$work/$component-release"
+  bash "$root/ci/release-manifest.sh" "$component" "$repository" "$digest" "$dev_tag" dev "$release_dir"
+  if [[ -n "${RELEASE_API_URL:-}" && -n "${RELEASE_API_TOKEN:-}" ]]; then
+    python3 -c 'import json,sys; print(json.dumps({"manifest": open(sys.argv[1]).read(), "signature": open(sys.argv[2]).read()}))'       "$release_dir/manifest.json" "$release_dir/manifest.sig"       | curl --fail-with-body --silent --show-error --retry 3 -X POST "${RELEASE_API_URL%/}/api/admin/releases"           -H "Authorization: Bearer $RELEASE_API_TOKEN" -H 'Content-Type: application/json' --data-binary @- >/dev/null
+    echo "registered the signed $component release with the panel"
+  fi
+fi