Adding a directory that belongs to an archived project fails with no way to restore it

## Bug description

In the desktop app, when you use **Add project** and pick a directory that belongs to a project that was previously **archived**, the action simply fails (the add flow treats it as a registration error). There is no indication that the directory matches an archived project, and no way to restore it from this flow — the user has to manually find and unarchive the project elsewhere first.

## Steps to reproduce

1. Archive a project (e.g. in Settings → Projects).
2. Use the workspace/task-entry **Add project** picker and select that project directory again.
3. The add fails with a generic error; nothing tells the user the project is archived or offers to restore it.

## Expected behavior

The app should detect that the chosen directory belongs to an archived project and offer to **restore** it in place, so that adding succeeds.

## Additional context

The runtime-host project/skill catalog coordinators also swallow `commit_outcome_unknown` mutation failures without logging, which makes failures like this hard to diagnose from logs.