Create GitHub Actions workflow to build zip (#2)

Introduce CI/CD workflow for on-demand ZIP build using GitHub Actions. 

This update implements a GitHub Action to automate the creation of a ZIP file for our WordPress plugin when it was run manually on GitHub, GitHub CLI, or the REST API. The ZIP is available for download immediately, facilitating rapid testing and deployment.

- Copied the bash commands from `tools/build_release.sh` as the build plugin action

.github/workflows/build-zip.yml

@@ -0,0 +1,54 @@
+name: Build release zip
+
+on:
+  workflow_dispatch
+
+jobs:
+  build:
+    name: Build release zip
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v4
+
+    - name: Build plugin # modify this step as needed
+      run: |
+        # run script from project root
+        EXEC_DIR=$(pwd)
+        
+        TMP_DIR="$EXEC_DIR/plugintmp"
+        rm -Rf "$TMP_DIR"
+        mkdir -p "$TMP_DIR"
+        
+        rm -Rf "$TMP_DIR/wp2static"
+        mkdir "$TMP_DIR/wp2static"
+        
+        # clear dev dependencies
+        rm -Rf "$EXEC_DIR/vendor/*"
+        # load prod deps and optimize loader
+        composer install --quiet --no-dev --optimize-autoloader
+        
+        # cp all required sources to build dir
+        cp -r "$EXEC_DIR"/src "$TMP_DIR"/wp2static/
+        cp -r "$EXEC_DIR"/vendor "$TMP_DIR"/wp2static/
+        cp -r "$EXEC_DIR"/views "$TMP_DIR"/wp2static/
+        cp -r "$EXEC_DIR"/css "$TMP_DIR"/wp2static/
+        cp -r "$EXEC_DIR"/js "$TMP_DIR"/wp2static/
+        cp -r "$EXEC_DIR"/*.php "$TMP_DIR"/wp2static/
+        
+        cd "$TMP_DIR" || exit
+        
+        # tidy permissions
+        find . -type d -exec chmod 755 {} \;
+        find . -type f -exec chmod 644 {} \;
+      shell: bash
+
+    - name: Upload the archive as an artifact
+      id: upload-plugin-artifact
+      uses: actions/upload-artifact@v4
+      with:
+        name: ${{ github.event.repository.name }}
+        path: plugintmp/wp2static
+
+