chore(ci): bump Node to 22 in build-perf workflow

Aligns with the Node 22 requirement introduced by start-server-and-test
3.0.0 and is consistent with the release workflow upgrade. Also adds an
explicit node-version to the build-time job which previously relied on
the runner default.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: sserrata

.github/workflows/build-perf.yml

@@ -20,7 +20,7 @@ jobs:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
       - uses: actions/setup-node@cdca7365b2dadb8aad0a33bc7601856ffabcc48e # v4
         with:
-          node-version: "20"
+          node-version: "22"
           cache: yarn
       - uses: preactjs/compressed-size-action@946a292cd35bd1088e0d7eb92b69d1a8d5b5d76a # v2
         with:
@@ -43,6 +43,7 @@ jobs:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
       - uses: actions/setup-node@cdca7365b2dadb8aad0a33bc7601856ffabcc48e # v4
         with:
+          node-version: "22"
           cache: yarn
       - name: Installation
         run: yarn