Update node version on CI

Author: emmatown

.github/actions/ci-setup/action.yml

@@ -10,7 +10,7 @@ runs:
     - uses: actions/setup-node@main
       with:
         # preferably lts/*, but we hit API limits when querying that
-        node-version: 20
+        node-version: 24
         registry-url: 'https://registry.npmjs.org'
         cache: pnpm