Add GitHub Pages deployment workflow and upgrade Docusaurus

- Add GitHub Actions workflow for automated deployment to GitHub Pages
- Upgrade Docusaurus from 3.4.0 to 3.9.2 with latest features and bug fixes
- Upgrade React from 18.3.1 to 19.2.0 for improved performance
- Upgrade MDX and prism-react-renderer dependencies
- Add CNAME file for custom domain (www.apexfp.org)
- Fix deprecated onBrokenMarkdownLinks config for Docusaurus v4 compatibility

The workflow builds and deploys the documentation site automatically on pushes to main branch.

Author: ipavlic

.github/workflows/website.yml

@@ -0,0 +1,66 @@
+name: Deploy Website
+
+on:
+  push:
+    branches:
+      - main
+    paths:
+      - 'website/**'
+      - '.github/workflows/website.yml'
+  pull_request:
+    branches:
+      - main
+    paths:
+      - 'website/**'
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+concurrency:
+  group: "pages"
+  cancel-in-progress: false
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: website
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: npm
+          cache-dependency-path: website/package-lock.json
+
+      - name: Setup Pages
+        uses: actions/configure-pages@v4
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Build website
+        run: npm run build
+
+      - name: Upload artifact
+        uses: actions/upload-pages-artifact@v3
+        with:
+          path: website/build
+
+  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

website/docusaurus.config.js

@@ -14,8 +14,12 @@ const config = {
   url: 'https://www.apexfp.org',
   baseUrl: '/',
   onBrokenLinks: 'throw',
-  onBrokenMarkdownLinks: 'warn',
   favicon: 'img/favicon.ico',
+  markdown: {
+    hooks: {
+      onBrokenMarkdownLinks: 'warn',
+    },
+  },
   organizationName: 'apex-fp', // Usually your GitHub org/user name.
   projectName: 'apex-fp', // Usually your repo name.