git: fix workflow to use npm

Author: will-break-it

.github/workflows/docs.yaml

@@ -147,12 +147,12 @@ jobs:
         uses: actions/setup-node@v4
         with:
           node-version: 22
-          cache: "yarn"
-          cache-dependency-path: ./site/yarn.lock
+          cache: "npm"
+          cache-dependency-path: ./site/package-lock.json
 
       - name: 📦 Install dependencies
         working-directory: site
-        run: yarn install
+        run: npm ci
 
       - name: 👁️ Unpack visualizer
         uses: actions/download-artifact@v4
@@ -163,7 +163,7 @@ jobs:
       - name: 🏗️ Build Docusaurus site
         working-directory: site
         run: |
-          yarn build
+          npm run build
 
       - name: Verify Docusaurus build
         working-directory: site