fix(ci): install node on alpine image

.forgejo/workflows/test.yaml

@@ -23,6 +23,19 @@ jobs:
     container:
       image: ${{ matrix.image }}
     steps:
+      - name: Install Node (Alpine only)
+        shell: sh
+        run: |
+          set -e
+
+          if ! command -v node >/dev/null 2>&1; then
+            if command -v apk >/dev/null 2>&1; then
+              apk add --no-cache nodejs
+            else
+              echo "::error::Node.js cannot be installed for this environment."
+              exit 1
+            fi
+          fi
       - uses: actions/checkout@v6
       - name: Test action
         uses: ./