chore(deps): update actions/setup-node action to v6

Author: renovate[bot]

.github/workflows/build.yaml

@@ -29,7 +29,7 @@ jobs:
     steps:
       - uses: actions/checkout@v6
       - name: Set up Node.js ${{ matrix.node-version }}
-        uses: actions/setup-node@v4
+        uses: actions/setup-node@v6
         with:
           node-version: ${{ matrix.node-version }}
       - name: Cache Node.js modules and Next.js build
@@ -113,7 +113,7 @@ jobs:
     steps:
       - uses: actions/checkout@v6
       - name: Set up Node.js 24
-        uses: actions/setup-node@v4
+        uses: actions/setup-node@v6
         with:
           node-version: 24.x
       - name: Cache Node.js modules
@@ -242,7 +242,7 @@ jobs:
         run: docker compose -f docker-compose.prod.yml down -v
 
       - name: Set up Node.js for cypress + seed script
-        uses: actions/setup-node@v4
+        uses: actions/setup-node@v6
         with:
           node-version: 24.x