Add actions/setup-node with node-version-file to all workflow jobs

- Added actions/setup-node@v4 with node-version-file: package.json to ci.yml Build job
- Added actions/setup-node@v4 with node-version-file: artifact/package.json to all esm-lint.yml jobs that run npm/npx commands
- Added actions/setup-node@v4 with node-version-file: package.json to demo.yml build job
- Ensures all jobs use the correct Node version as specified in package.json engines field

Co-authored-by: fregante <1402241+fregante@users.noreply.github.com>

Author: Copilot

.github/workflows/ci.yml

@@ -29,6 +29,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version-file: package.json
       - run: npm ci
       - run: npm run build
       - name: Ensure that test URLs aren't included in the built file

.github/workflows/demo.yml

@@ -16,6 +16,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version-file: package.json
       - run: npm ci
       - run: npm run build:demo
       - run: npm run test:demo

.github/workflows/esm-lint.yml

@@ -19,6 +19,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version-file: package.json
       - run: npm install
       - run: npm run build --if-present
       - run: npm pack --dry-run
@@ -31,12 +34,18 @@ jobs:
     needs: Pack
     steps:
       - uses: actions/download-artifact@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version-file: artifact/package.json
       - run: npx publint ./artifact
   Webpack:
     runs-on: ubuntu-latest
     needs: Pack
     steps:
       - uses: actions/download-artifact@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version-file: artifact/package.json
       - run: npm install --omit=dev ./artifact
       - run: echo "$IMPORT_STATEMENT" > index.js
       - run: webpack --entry ./index.js
@@ -46,6 +55,9 @@ jobs:
     needs: Pack
     steps:
       - uses: actions/download-artifact@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version-file: artifact/package.json
       - run: npm install --omit=dev ./artifact
       - run: echo "$IMPORT_STATEMENT" > index.js
       - run: >
@@ -58,6 +70,9 @@ jobs:
     needs: Pack
     steps:
       - uses: actions/download-artifact@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version-file: artifact/package.json
       - run: npm install --omit=dev ./artifact rollup@4 @rollup/plugin-json @rollup/plugin-node-resolve
       - run: echo "$IMPORT_STATEMENT" > index.js
       - run: npx rollup -p node-resolve -p @rollup/plugin-json index.js
@@ -66,6 +81,9 @@ jobs:
     needs: Pack
     steps:
       - uses: actions/download-artifact@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version-file: artifact/package.json
       - run: npm install --omit=dev ./artifact
       - run: echo '<script type="module">$IMPORT_STATEMENT</script>' > index.html
       - run: npx vite build
@@ -75,6 +93,9 @@ jobs:
     needs: Pack
     steps:
       - uses: actions/download-artifact@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version-file: artifact/package.json
       - run: echo '{}' > package.json
       - run: echo "$IMPORT_STATEMENT" > index.js
       - run: npm install --omit=dev ./artifact
@@ -84,6 +105,9 @@ jobs:
     needs: Pack
     steps:
       - uses: actions/download-artifact@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version-file: artifact/package.json
       - run: echo '{"type":"module"}' > package.json
       - run: npm install --omit=dev ./artifact @sindresorhus/tsconfig
       - run: echo "$IMPORT_STATEMENT" > index.ts