fix: add npm install for SonarCloud TypeScript analysis

SonarCloud needs node_modules to resolve tsconfig references.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: braboj

.github/workflows/sonarcloud.yml

@@ -17,6 +17,17 @@ jobs:
         with:
           fetch-depth: 0
 
+      - name: Set up Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: "22.12.0"
+          cache: npm
+          cache-dependency-path: astro-site/package-lock.json
+
+      - name: Install dependencies
+        working-directory: astro-site
+        run: npm ci
+
       - name: SonarCloud Scan
         uses: SonarSource/sonarqube-scan-action@v6
         env: