ci: add Build Test workflow as the required status check

.github/workflows/build-test.yml

@@ -0,0 +1,45 @@
+name: Build Test
+
+# Mirrors the build steps from deploy-docs.yml so that any PR that would
+# break the deploy fails CI here first. Runs unconditionally on every PR
+# and every push to main, providing the always-on required status check
+# for branch protection. The deploy-only steps (WordPress upload,
+# translation, GitHub release) are not exercised — they require live
+# external services and run only on tag.
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+jobs:
+  build:
+    name: Build governance docs
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+
+      - name: Install pandoc
+        uses: pandoc/actions/setup@86321b6dd4675f5014c611e05088e10d4939e09e # v1.1.1
+
+      - name: Setup Node.js
+        uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e # v6
+        with:
+          node-version: '24'
+          cache: 'npm'
+
+      - name: Install npm dependencies
+        run: npm ci
+        env:
+          PUPPETEER_SKIP_DOWNLOAD: 'true'
+
+      - name: Build standalone HTML pages
+        run: npm run build:html
+
+      - name: Build combined PDF
+        run: npm run build:pdf
+        env:
+          PUPPETEER_EXECUTABLE_PATH: /usr/bin/google-chrome-stable