* Start replacing jotai with @tanstack/router
* Remove jotai completely
* Move the common layout & reimplement the ?action parameter
This also makes sure everything is properly loaded in the route loader,
and we use fragment where it makes sense
* Change the default error component
* GraphQL API: make the sessions fetchable through node(id: ID!)
This makes the Vite assets handling better, namely:
- make it possible to include any vite assets in the templates
- include the right `<link rel="preload">` tags for assets
- include Subresource Integrity hashes
- pre-compress assets and remove on-the-fly compression by the Rust server
- build the CSS used by templates through Vite
It also moves the React app from /app/ to /account/, and remove some of the old SSR account screens.
This cuts the bundle size by 50% and makes it easier to reason about state.
It removes the usage of react-router-dom and replaces it with a simple router atom based on jotai-location.
Since the screens will be quite simple, I don't expect that we'll need the advanced caching features of react-relay, hence the switch to urql.
