Add GitHub Actions workflow for website deployment

Creates automated build and deployment pipeline for the documentation website:

Workflow features:
- Triggers on push to main or create-documentation-site-for-keymaps branch
- Triggers on changes to layout.yaml, website/, scripts/, or workflow file
- Manual trigger via workflow_dispatch

Build steps:
1. Setup Python 3.12 for keymap-drawer
2. Setup Node.js 20 for Eleventy
3. Install dependencies (keymap-drawer, npm packages)
4. Generate SVG diagrams from layout.yaml
5. Build static site with Eleventy
6. Create .nojekyll file to disable Jekyll processing
7. Deploy to GitHub Pages

The workflow uses the official GitHub Pages deployment actions and includes
proper permissions and concurrency controls to prevent deployment conflicts.

Next step: Enable GitHub Pages in repository settings
(Settings → Pages → Source: GitHub Actions)

.github/workflows/build_website.yaml

@@ -0,0 +1,78 @@
+name: Build and Deploy Documentation Website
+
+on:
+  push:
+    branches:
+      - main
+      - create-documentation-site-for-keymaps
+    paths:
+      - 'keyboards/**/layout.yaml'
+      - 'website/**'
+      - 'scripts/**'
+      - '.github/workflows/build_website.yaml'
+  workflow_dispatch:
+
+# Sets permissions of the GITHUB_TOKEN to allow deployment to GitHub Pages
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+# Allow only one concurrent deployment, skipping runs queued between the run in-progress and latest queued.
+# However, do NOT cancel in-progress runs as we want to allow these production deployments to complete.
+concurrency:
+  group: "pages"
+  cancel-in-progress: false
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Setup Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.12'
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+          cache: 'npm'
+          cache-dependency-path: website/package-lock.json
+
+      - name: Install keymap-drawer
+        run: pip install keymap-drawer
+
+      - name: Install Node.js dependencies
+        working-directory: website
+        run: npm ci
+
+      - name: Generate SVG diagrams
+        run: node scripts/generate-svgs.js
+
+      - name: Build website with Eleventy
+        working-directory: website
+        run: npm run build
+
+      - name: Create .nojekyll file
+        working-directory: website
+        run: touch _site/.nojekyll
+
+      - name: Upload artifact
+        uses: actions/upload-pages-artifact@v3
+        with:
+          path: website/_site
+
+  deploy:
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    runs-on: ubuntu-latest
+    needs: build
+    steps:
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v4