Migrate website from GitHub Pages to OpenAEC server

[JohnHeikens]

What changed

• Delete the reusable GitHub Pages deployment workflow.
• Remove the Pages job from the main pipeline.
• Add a server-only deployment workflow using OpenAEC-Foundation/github/.github/workflows/deploy-site.yml@main.
• Build the browser IDE and sync the complete web/ root to /var/www/dynlex.com.

Hosting migration

• GitHub Pages is disabled for this repository.
• dynlex.com and www.dynlex.com now resolve to the OpenAEC server over IPv4 and IPv6.
• Nginx serves both hostnames from /var/www/dynlex.com.
• Let’s Encrypt TLS is active for both hostnames with automatic renewal through the existing TransIP DNS hooks.
• A repository-specific deployment key, DEPLOY_HOST, DEPLOY_PORT, and DEPLOY_USER are configured for Actions.

Checks

• full ./scripts/test.sh: 124 passed, 0 failed, 0 skipped
• production web build with Node.js 22
• WebAssembly compiler assets present in the deployed web root
• actionlint .github/workflows/*.yml
• git diff --check
• Nginx configuration test
• direct HTTPS checks for the home page, IDE, and WebAssembly asset
• authoritative TransIP DNS plus Cloudflare, Google, and Quad9 resolver checks