Bump CI actions to Node 24 versions (checkout v7, setup-node v6, cache v5)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: jonfroehlich

.github/workflows/build-gallery.yml

@@ -10,10 +10,10 @@ jobs:
     permissions:
       contents: write
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
 
       - name: Set up Node
-        uses: actions/setup-node@v4
+        uses: actions/setup-node@v6
         with:
           node-version: 20
           cache: npm
@@ -27,7 +27,7 @@ jobs:
       # Cache Playwright's bundled Chromium across runs (keyed on the lockfile,
       # which pins the Playwright version).
       - name: Cache Playwright browsers
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: ~/.cache/ms-playwright
           key: playwright-${{ runner.os }}-${{ hashFiles('package-lock.json') }}