cicd: fix job environments

Author: gfauredev

.github/workflows/cd.yml

@@ -8,13 +8,8 @@ jobs:
   release:
     timeout-minutes: 5
     runs-on: ubuntu-latest
-    environment:
-      name: github-pages
-      url: ${{ steps.deployment.outputs.page_url }}
     permissions:
       contents: write
-      pages: write
-      id-token: write
     env:
       GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
     steps:
@@ -40,10 +35,29 @@ jobs:
       run: |
         TAG=${GITHUB_REF#refs/tags/}
         gh release create "$TAG" *.json --title "$TAG" --notes "Release $TAG"
-    - run: |
-        mkdir --verbose dist/
-        mv --verbose exercises*.json dist/
-        cp --verbose i18n.json dist/
+
+  pages:
+    timeout-minutes: 5
+    runs-on: ubuntu-latest
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    permissions:
+      contents: read
+      pages: write
+      id-token: write
+    env:
+      GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+    steps:
+    - uses: actions/checkout@v6
+    - uses: cachix/install-nix-action@v31
+      with:
+        github_access_token: ${{ secrets.GITHUB_TOKEN }}
+        extra_nix_config: |
+          extra-substituters = https://cache.garnix.io
+          extra-trusted-public-keys = cache.garnix.io:CTFPyKSLcx5RMJKfLo5EEPUObbA78b0YQ2DTCJXqr9g=
+    - uses: DeterminateSystems/magic-nix-cache-action@v13
+    - run: nix develop -c just dist
     - uses: actions/upload-pages-artifact@v4
       with: { path: ./dist }
     - uses: actions/deploy-pages@v4
@@ -57,7 +71,6 @@ jobs:
       GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
     permissions:
       contents: write
-      id-token: write
     steps:
     - run: | # Cleanup rolling releases > 7 days or < 12 hours
         gh release list --json tagName,createdAt,isPrerelease \