test: PoC publish via artifact-gateway with dd-pkg image

Replace publish_public_main trigger block with dd-pkg publish-image.
Uses staging gateway, test destination (agent-dev:gateway-operator-poc-test),
registry.datad0g.com only. Manual trigger for safety.

BARX-1709

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: AliDatadog

.gitlab-ci.yml

@@ -464,19 +464,20 @@ e2e_autoscaling:
 
 publish_public_main:
   stage: release
+  image: registry.ddbuild.io/agent-delivery/dd-pkg:v106852116-3c888529
+  tags: ["arch:amd64"]
   rules:
-    - if: '$CI_COMMIT_BRANCH == "main" && $DDR != "true"'
-      when: on_success
-    - when: never
-  trigger:
-    project: DataDog/public-images
-    branch: main
-    strategy: depend
+    - when: manual
+      allow_failure: true
+  before_script: []
   variables:
-    IMG_SOURCES: $BUILD_DOCKER_REGISTRY/$PROJECTNAME:v${CI_PIPELINE_ID}-${CI_COMMIT_SHORT_SHA}-amd64,$BUILD_DOCKER_REGISTRY/$PROJECTNAME:v${CI_PIPELINE_ID}-${CI_COMMIT_SHORT_SHA}-arm64
-    IMG_DESTINATIONS: operator:main
+    IMG_SOURCES: $BUILD_DOCKER_REGISTRY/$PROJECTNAME:v${CI_PIPELINE_ID}-${CI_COMMIT_SHORT_SHA}-amd64
+    IMG_DESTINATIONS: operator-dev:gateway-poc-${CI_PIPELINE_ID}
+    IMG_REGISTRIES: "registry.datad0g.com"
     IMG_SIGNING: "false"
-    IMG_MERGE_STRATEGY: "index_oci"
+    ARTIFACT_GATEWAY_URL: "https://artifact-gateway.us1.ddbuild.staging.dog/internal/artifact-gateway"
+  script:
+    - dd-pkg publish-image --gateway-url "${ARTIFACT_GATEWAY_URL}" --timeout 1800
 
 publish_public_main_fips:
   extends: publish_public_main