ci(docs): validate typecheck and production build

.github/workflows/docs.yml

@@ -0,0 +1,47 @@
+name: Docs website
+
+on:
+  pull_request:
+    paths:
+      - "docs/**"
+      - ".github/workflows/docs.yml"
+  push:
+    branches:
+      - master
+    paths:
+      - "docs/**"
+      - ".github/workflows/docs.yml"
+
+permissions:
+  contents: read
+
+concurrency:
+  group: docs-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  quality:
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+    defaults:
+      run:
+        working-directory: docs
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: "22"
+          cache: npm
+          cache-dependency-path: docs/package-lock.json
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Type-check
+        run: npm run typecheck
+
+      - name: Build
+        run: npm run build

.gitignore

@@ -22,3 +22,4 @@ target/
 
 # Local design export scratch
 output/
+.screenshots