Address review feedback: mountedRoutes are for abstract route targets
the test subject links to, not for the subject itself. Add a dedicated
mountPath option that wraps the test element in a single Route with
the given path pattern, enabling useParams(). When mountPath is set
and initialRouteEntries is not, the initial entry defaults to mountPath.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Signed-off-by: Fredrik Adelöw <freben@gmail.com>