ci: add a temporary workflow that lists the arch tags to remove

- scripts/tmp-remove-arch-tags.sh lists the arch tags such as 4.1.2-amd64 whose image a multi-platform tag still reaches, and removes as many as --remove asks for
- A registry deletes a tag only with its image, so --remove moves each arch tag to a placeholder manifest and deletes the placeholder, the image stays, as the multi-platform manifest points at it by digest

.github/workflows/tmp-remove-arch-tags.yaml

@@ -0,0 +1,48 @@
+name: TMP Remove arch tags
+
+on:
+  workflow_dispatch:
+
+permissions: {}
+
+cache-mode: none
+
+concurrency:
+  group: clean-manifests
+  cancel-in-progress: false
+
+defaults:
+  run:
+    shell: bash
+
+jobs:
+  remove:
+    name: Remove arch tags
+    if: ${{ github.repository == 'coollabsio/coolify' }}
+    permissions:
+      contents: read
+    environment:
+      name: cleanup
+      deployment: false
+    runs-on: ubuntu-26.04 # https://github.com/actions/runner-images
+    timeout-minutes: 60
+    steps:
+      - name: Check out the repository
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          persist-credentials: false
+
+      - name: List the arch tags to remove
+        env:
+          DOCKERHUB_USERNAME: ${{ secrets.DOCKERHUB_CLEANUP_USERNAME }}
+          DOCKERHUB_TOKEN: ${{ secrets.DOCKERHUB_CLEANUP_TOKEN }}
+        run: scripts/tmp-remove-arch-tags.sh
+
+      - name: Upload the list of arch tags to remove
+        if: ${{ always() }}
+        uses: actions/upload-artifact@cf430e030ddbb5b0abf93d22962f4752f3646cd9 # v7.0.2
+        with:
+          name: arch-tags-to-remove
+          path: scripts/arch-tags-to-remove.tsv
+          if-no-files-found: ignore
+          retention-days: 90