Add GitHub Actions workflow for publishing plugin

- Introduced a new workflow file (.github/workflows/publish.yml) to automate the publishing process for the plugin.
- Configured jobs for testing and publishing to NPM upon version tag pushes.
- Included steps for dependency installation, plugin building, and verification before publishing.
- Ensured integration tests are run in the playground environment before publishing the plugin.

.github/workflows/publish.yml

@@ -0,0 +1,72 @@
+name: Publish
+
+on:
+  push:
+    tags:
+      - "v*"
+
+permissions:
+  contents: read
+  id-token: write
+
+jobs:
+  test:
+    name: Tests
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Setup Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: 22
+          cache: "npm"
+          cache-dependency-path: |
+            package-lock.json
+            playground/package-lock.json
+      - name: Write playground .env
+        run: |
+          printf '%s' "${{ secrets.PLAYGROUND_ENV_BASE64 }}" | base64 -d > playground/.env
+      - name: Install root deps
+        run: npm ci
+      - name: Build plugin
+        run: npm run build
+      - name: Verify plugin
+        run: npm run verify
+      - name: Pack plugin into playground .yalc
+        run: |
+          TARBALL=$(npm pack --silent)
+          mkdir -p playground/.yalc/strapi-plugin-checkbox-list
+          tar -xzf "$TARBALL" -C playground/.yalc/strapi-plugin-checkbox-list --strip-components=1
+      - name: Install playground deps
+        working-directory: playground
+        run: npm install
+      - name: Build playground
+        working-directory: playground
+        run: npm run build
+      - name: Integration tests
+        working-directory: playground
+        run: npm run test:integration
+
+  publish:
+    name: Publish to NPM (Trusted Publisher)
+    runs-on: ubuntu-latest
+    needs: test
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Setup Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: 22
+          registry-url: https://registry.npmjs.org/
+          cache: "npm"
+          cache-dependency-path: package-lock.json
+      - name: Install deps
+        run: npm ci
+      - name: Build plugin
+        run: npm run build
+      - name: Verify plugin
+        run: npm run verify
+      - name: Publish
+        run: npm publish