Add Service Worker

[jbmoelker]

User story

As a website visitor,
I want web pages to be cached,
so I get a fast and reliable experience.

Strategy

Add a Service Worker with a strategy to use recently cached pages (x minutes ago?), then try the network (if older or not in cache), then cache (if network fails, and an older cached page is at least still available).

We could use Workbox for this.

[jbmoelker]

• Deep dive article on ways to include a service worker in Astro: https://rumaan.dev/blog/workbox-astro-project
• Prior art: https://github.com/tatethurston/astrojs-service-worker