diff --git a/.github/workflows/build_joomla_zip.yml b/.github/workflows/build_joomla_zip.yml
new file mode 100644
index 0000000..4d9f7e0
--- /dev/null
+++ b/.github/workflows/build_joomla_zip.yml
@@ -0,0 +1,158 @@
+name: Build Joomla ZIP from src folder
+
+on:
+   workflow_dispatch:
+      inputs:
+         attach_to_release:
+            description: "Attach ZIP to a GitHub Release"
+            required: true
+            default: "false"
+            type: choice
+            options:
+               - "false"
+               - "true"
+         release_tag:
+            description: "Release tag to upload to. If blank, defaults to dev/<version> using templateDetails.xml (example dev/03.02.00)"
+            required: false
+            default: ""
+
+permissions:
+   contents: write
+
+jobs:
+   build:
+      name: Package template
+      runs-on: ubuntu-latest
+
+      env:
+         TEMPLATE_DIR: src/templates/moko-cassiopeia
+         SRC_LANGUAGE_DIR: src/language
+         SRC_MEDIA_DIR: src/media
+         OUT_DIR: dist
+         STAGE_DIR: dist/stage
+         ZIP_BASENAME: moko-cassiopeia
+
+      steps:
+         - name: Checkout
+            uses: actions/checkout@v4
+
+         - name: Build staging package and ZIP
+            id: pkg
+            shell: bash
+            run: |
+               set -euo pipefail
+
+               rm -rf "${OUT_DIR}"
+               mkdir -p "${STAGE_DIR}"
+
+               # Validate template source
+               if [ ! -f "${TEMPLATE_DIR}/templateDetails.xml" ]; then
+                  echo "ERROR: Missing ${TEMPLATE_DIR}/templateDetails.xml"
+                  exit 1
+               fi
+
+               # Flatten template root into stage root
+               cp -R "${TEMPLATE_DIR}/." "${STAGE_DIR}/"
+
+               # Copy language and media to stage root if present
+               if [ -d "${SRC_LANGUAGE_DIR}" ]; then
+                  cp -R "${SRC_LANGUAGE_DIR}" "${STAGE_DIR}/language"
+               fi
+
+               if [ -d "${SRC_MEDIA_DIR}" ]; then
+                  cp -R "${SRC_MEDIA_DIR}" "${STAGE_DIR}/media"
+               fi
+
+               # Hard checks for installer-critical items
+               test -f "${STAGE_DIR}/templateDetails.xml"
+               test -f "${STAGE_DIR}/index.php"
+               test -f "${STAGE_DIR}/component.php"
+
+               # Read version from manifest
+               VERSION="$(python - << 'PY'
+               import xml.etree.ElementTree as ET
+               root = ET.parse("dist/stage/templateDetails.xml").getroot()
+               v = root.findtext("version") or ""
+               v = v.strip()
+               if not v:
+                  raise SystemExit("ERROR: <version> not found in templateDetails.xml")
+               print(v)
+               PY
+               )"
+
+               ZIP_NAME="${ZIP_BASENAME}-${VERSION}.zip"
+               ZIP_PATH="${OUT_DIR}/${ZIP_NAME}"
+
+               (cd "${STAGE_DIR}" && zip -r "../${ZIP_NAME}" .)
+
+               echo "version=${VERSION}" >> "${GITHUB_OUTPUT}"
+               echo "zip_name=${ZIP_NAME}" >> "${GITHUB_OUTPUT}"
+               echo "zip_path=${ZIP_PATH}" >> "${GITHUB_OUTPUT}"
+
+         - name: Compute effective release tag
+            id: tag
+            shell: bash
+            run: |
+               set -euo pipefail
+
+               INPUT_TAG="${{ github.event.inputs.release_tag }}"
+               INPUT_TAG="$(echo "${INPUT_TAG}" | tr -d '[:space:]')"
+
+               if [ -n "${INPUT_TAG}" ]; then
+                  EFFECTIVE_TAG="${INPUT_TAG}"
+               else
+                  EFFECTIVE_TAG="dev/${{ steps.pkg.outputs.version }}"
+               fi
+
+               echo "effective_tag=${EFFECTIVE_TAG}" >> "${GITHUB_OUTPUT}"
+
+         - name: Upload workflow artifact (temporary)
+            uses: actions/upload-artifact@v4
+            with:
+               name: ${{ steps.pkg.outputs.zip_name }}
+               path: ${{ steps.pkg.outputs.zip_path }}
+               retention-days: 30
+
+         - name: Attach ZIP to GitHub Release (optional)
+            if: ${{ github.event.inputs.attach_to_release == 'true' }}
+            env:
+               GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+            shell: bash
+            run: |
+               set -euo pipefail
+
+               TAG="${{ steps.tag.outputs.effective_tag }}"
+               ZIP="${{ steps.pkg.outputs.zip_path }}"
+
+               if [ -z "${TAG}" ]; then
+                  echo "ERROR: release tag is empty."
+                  exit 1
+               fi
+
+               # Ensure the tag exists locally for release creation (optional)
+               # GitHub will still allow creating a release for a tag name, but tagging is best practice.
+               if ! git rev-parse -q --verify "refs/tags/${TAG}" >/dev/null 2>&1; then
+                  echo "INFO: Tag ${TAG} not found locally. Creating lightweight tag on current commit."
+                  git tag "${TAG}"
+                  git push origin "${TAG}"
+               fi
+
+               # Create release if missing, then upload asset with clobber
+               if ! gh release view "${TAG}" >/dev/null 2>&1; then
+                  gh release create "${TAG}" \
+                     --title "${TAG}" \
+                     --notes "Automated build artifact upload." \
+                     --draft
+               fi
+
+               # Upload asset
+               set +e
+               gh release upload "${TAG}" "${ZIP}" --clobber
+               RC=$?
+               set -e
+
+               if [ $RC -ne 0 ]; then
+                  echo "ERROR: Failed to upload asset to release ${TAG}."
+                  echo "NOTE: GitHub may reject uploads to an immutable release. If so, create a new draft release or a new tag and retry."
+                  exit $RC
+               fi