Build and test with Node 24 in CI

The .nvmrc file these workflows used to read the Node version from was
removed in #420, so the version is written into the setup-node steps
directly. Keep it in sync with the node24 runtime the action declares.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: hsbt

.github/workflows/check-dist.yml

@@ -31,7 +31,7 @@ jobs:
       - name: Set up Node.js
         uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e # v6.4.0
         with:
-          node-version: '20'
+          node-version: '24'
 
       - name: Install dependencies
         run: npm ci

.github/workflows/compile-dependabot-updates.yml

@@ -20,7 +20,7 @@ jobs:
       - name: Set up Node
         uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e # v6.4.0
         with:
-          node-version: '20'
+          node-version: '24'
           cache: 'npm'
 
       - name: Install dependencies