Fix GitHub Actions: Use yarn instead of npm for deploy-pages workflow

Author: TRK95

.github/workflows/deploy-pages.yml

@@ -25,13 +25,13 @@ jobs:
         uses: actions/setup-node@v4
         with:
           node-version: '20'
-          cache: 'npm'
+          cache: 'yarn'
 
       - name: Install dependencies
-        run: npm ci
+        run: yarn install
 
       - name: Build project
-        run: npm run build
+        run: yarn build
 
       - name: Setup Pages
         uses: actions/configure-pages@v4