feat: Add differ CI job

.github/workflows/differ.yml

@@ -0,0 +1,30 @@
+name: Differ
+
+on:
+  workflow_run:
+    workflows: [Vib Build]
+    types:
+      - completed
+
+jobs:
+  differ:
+    runs-on: ubuntu-latest
+    container:
+      image: ghcr.io/vanilla-os/core:main
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Generate package diff
+        run: |
+          PACKAGE_LIST=$(.github/gen_package_list.sh)
+          apt-get install -y curl
+          IMAGE_DIGEST=$(curl -s -L -H "Accept: application/vnd.github+json" \
+          -H "Authorization: Bearer ${{ secrets.GITHUB_TOKEN }}" \
+          -H "X-GitHub-Api-Version: 2022-11-28" \
+          https://api.github.com/orgs/Vanilla-OS/packages/container/core/versions | grep -m1 name | sed -E 's/^\s*"name": "(.+)".*$/\1/')
+          curl -X POST \
+          -H 'Accept:application/json' \
+          -H "Authorization:Basic $(echo -n "${{ secrets.DIFFER_USER }}:${{ secrets.DIFFER_PSW }}" | base64)" \
+          -d "{\"digest\":\"${IMAGE_DIGEST}\",${PACKAGE_LIST}}" \
+          ${{ vars.DIFFER_URL }}/images/core/new