This PR updates the project status service (and schemas and UI) to use
the project's current health instead of the 4-week average.
I nabbed the `calculateHealthRating` from
`src/lib/services/project-health-service.ts` instead of relying on the
service itself, because that service relies on the project service,
which relies on pretty much everything in the entire system.
However, I think we can split the health service into a service that
*does* need the project service (which is used for 1 of 3 methods) and a
service (or read model) that doesn't. We could then rely on the second
one for this service without too much overhead. Or we could extract the
`calculateHealthRating` into a shared function that takes its stores as
arguments. ... but I suggest doing that in a follow-up PR.
Because the calculation has been tested other places (especially if we
rely on a service / shared function for it), I've simplified the tests
to just verify that it's present.
I've changed the schema's `averageHealth` into an object in case we want
to include average health etc. in the future, but this is up for debate.
