fix(ci): gate all integration jobs against dependabot

The dependabot actor check was only on the build job. The container-image
and cleanup-images jobs still ran — cleanup-images with if: always()
deleted GHCR container images while the main branch integration run was
still using them, causing PVE 8 tests to fail with "image not found".

Now all four integration jobs (build, container-image, integration,
cleanup-images) are gated with github.actor != 'dependabot[bot]'.

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

.github/workflows/integration-tests.yml

@@ -71,6 +71,7 @@ jobs:
 
   # ── Build test container image (GitHub-hosted) ───────────────────────
   container-image:
+    if: github.actor != 'dependabot[bot]'
     runs-on: ubuntu-latest
     timeout-minutes: 20
     steps:
@@ -94,7 +95,7 @@ jobs:
   # ── Clean up old container images from GHCR ──────────────────────────
   cleanup-images:
     needs: integration
-    if: always()
+    if: always() && github.actor != 'dependabot[bot]'
     runs-on: ubuntu-latest
     timeout-minutes: 5
     env: