Replace the controller-side error-string match with a shared, code-aware
helper. Go error types don't survive the gRPC boundary, so the signal is
carried as a status code (FailedPrecondition):
- pkg/grpc/grpcerrors: ModelNotLoaded(backend) constructor +
IsModelNotLoaded(err) checker (status-code first, message fallback for
backends not yet migrated).
- InFlightTrackingClient.reconcile now uses grpcerrors.IsModelNotLoaded.
- Migrate the Go backends that emit this error (parakeet-cpp, cloud-proxy,
rfdetr-cpp) to the typed constructor.
Acting on a false positive is harmless (the model is just reloaded).
Assisted-by: Claude:claude-opus-4-8 go vet
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>