ci: change actions to DeterminateSystems

.forgejo/workflows/ci.yml

@@ -15,16 +15,11 @@ jobs:
         uses: actions/checkout@v6
 
       - name: Install Nix
-        uses: cachix/install-nix-action@v31
-        with:
-          nix_path: nixpkgs=channel:nixos-unstable
-          extra_nix_config: |
-            sandbox = true
+        uses: DeterminateSystems/nix-installer-action@main
+      - uses: DeterminateSystems/magic-nix-cache-action@main
 
-      - name: Enable flakes
-        run: |
-          mkdir -p ~/.config/nix
-          echo "experimental-features = nix-command flakes" >> ~/.config/nix/nix.conf
+      - name: Check Nix flake inputs
+        uses: DeterminateSystems/flake-checker-action@main
 
       - name: Setup SOPS key
         if: env.SOPS_AGE_KEY != ''
@@ -34,12 +29,6 @@ jobs:
         env:
           SOPS_AGE_KEY: ${{ secrets.SOPS_AGE_KEY }}
 
-      - name: Flake check
-        run: nix flake check
-
-      - name: Remove homeless-shelter
-        run: rm -rf /homeless-shelter
-
       - name: Build all hosts
         run: |
           nix flake show --json | jq -r '