Server-only ErrorBoundaries

[mihhail-lapushkin]

Let's say I call an API in loaders and actions, and pass an auth token to it.

• If the token expires, the API returns 401. In this case, I want to redirect to login.
• If the API returns 500 inside an action, I want to set a global flash message that is rendered in an error toast by the root route.

Currently, there does not seem to be a way to define a common error handler to support these cases.

ErrorBoundary is the only common error handling mechanism, and it expects to render a UI, but I want to perform backend-y logic instead.