add CI images to repo

.forgejo/workflows/images.yaml

@@ -0,0 +1,16 @@
+on: [push]
+jobs:
+  check:
+    runs-on: nix-upstream-latest
+    steps:
+      - run: echo "experimental-features = nix-command flakes" >> /etc/nix/nix.conf
+      - run: nix-env -i nodejs skopeo # bootstrap
+      - uses: actions/checkout@v4
+      - run: mkdir -p /etc/containers && cp .forgejo/default-policy.json /etc/containers/policy.json
+      - run: |-
+          for line in $(cat .forgejo/tags.txt); do
+            IFS=: read -r pkg tag <<< $line
+            cp $(nix build .#$pkg --print-out-paths) /tmp/img.tar.gz
+            gunzip /tmp/img.tar.gz
+            skopeo copy --dest-creds="${{ secrets.FJ_USER }}:${{ secrets.FJ_PASS }}" docker-archive:///tmp/img.tar docker://git.10110110.xyz/ci/$tag:latest
+          done

.forgejo/workflows/main.yml

@@ -13,7 +13,8 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - uses: DeterminateSystems/nix-installer-action@main
-      - name: check
+      - uses: DeterminateSystems/flakehub-cache-action@main
+      - name: nix flake check
         run: nix flake check
       - name: Run `nix bundle`
         if: github.ref == 'refs/heads/main'