Refactor HTML build step to create and upload a zip archive

.forgejo/workflows/serve.yaml

@@ -15,15 +15,13 @@ jobs:
       - name: Build PDF exports
         run: uv run myst build --execute --pdf
       - name: Build static HTML
-        run: uv run myst build --execute --html
-      - name: Copy files
-        uses: forgejo/upload-artifact@v4
-        with:
-          name: srv
-          path: _build/html
+        run: |
+          uv run myst build --execute --html
+          mkdir -p /tmp/release
+          zip -r /tmp/release/html.zip _build/html
       - name: Make release
         uses: actions/forgejo-release@v2.6.0
         with:
           direction: upload
-          release-dir: _build/html
+          release-dir: /tmp/release
           token: ${{ secrets.FORGEJO_TOKEN }}