Express 5

[mrjvs]

Changes:

• Update to Node 24
• Update to express 5 using a migration guide.
  • Note: the app.listen() error change seems to be a lie, I cannot reproduce it and typescript says it doesnt exist
• Migrate away from express-subdomain and use the same code and technique as website and account repo uses
  • Breaking change: juxt-dev domains dont work by default anyway, they need a config change
• Remove dependabot.yml. It's too spammy, now it will only make PRs for security vulnerabilities. We will do manual updates for other libraries.

I've ran both servers and clicked through a bunch of juxt pages, seems to work fine

Resolves #123
Resolves #236

[ashquarky]

I propose we review this after #450