Install Dart Sass from upstream tarball instead of snap

The dart-sass-embedded snap is deprecated and snap store outages
were causing transient failures ("unable to contact snap store").
Pulling the prebuilt binary from the sass/dart-sass GitHub release
is what Hugo's official docs now recommend.

Author: yqtian-se

.github/workflows/pr-preview.yml

@@ -36,8 +36,14 @@ jobs:
         run: |
           wget -O ${{ runner.temp }}/hugo.deb https://github.com/gohugoio/hugo/releases/download/v${HUGO_VERSION}/hugo_extended_${HUGO_VERSION}_linux-amd64.deb \
           && sudo dpkg -i ${{ runner.temp }}/hugo.deb
-      - name: Install Dart Sass Embedded
-        run: sudo snap install dart-sass-embedded
+      - name: Install Dart Sass
+        env:
+          DART_SASS_VERSION: 1.83.4
+        run: |
+          wget -O /tmp/dart-sass.tar.gz \
+            "https://github.com/sass/dart-sass/releases/download/${DART_SASS_VERSION}/dart-sass-${DART_SASS_VERSION}-linux-x64.tar.gz"
+          tar -xf /tmp/dart-sass.tar.gz -C /tmp
+          echo "/tmp/dart-sass" >> $GITHUB_PATH
       - name: Setup Pages
         id: pages
         uses: actions/configure-pages@v5

.github/workflows/production-deploy.yml

@@ -36,8 +36,14 @@ jobs:
         run: |
           wget -O ${{ runner.temp }}/hugo.deb https://github.com/gohugoio/hugo/releases/download/v${HUGO_VERSION}/hugo_extended_${HUGO_VERSION}_linux-amd64.deb \
           && sudo dpkg -i ${{ runner.temp }}/hugo.deb
-      - name: Install Dart Sass Embedded
-        run: sudo snap install dart-sass-embedded
+      - name: Install Dart Sass
+        env:
+          DART_SASS_VERSION: 1.83.4
+        run: |
+          wget -O /tmp/dart-sass.tar.gz \
+            "https://github.com/sass/dart-sass/releases/download/${DART_SASS_VERSION}/dart-sass-${DART_SASS_VERSION}-linux-x64.tar.gz"
+          tar -xf /tmp/dart-sass.tar.gz -C /tmp
+          echo "/tmp/dart-sass" >> $GITHUB_PATH
       - name: Checkout
         uses: actions/checkout@v4
         with: