Sort imports in test_pred_type to satisfy ruff I001 (#35)

## What
Sorts the import block at `tests/test_pred_type.py:18` so `ruff` (rule
I001) passes clean on `main`.

```diff
-from NRS.nodes_NRS import PredictionType, _RAW_TO_ENUM, NRS
+from NRS.nodes_NRS import _RAW_TO_ENUM, NRS, PredictionType
```

## Why
Gate-1 (pre-refactor checkpoint) requires `ruff` + `pytest` green on
`main`. This was the only outstanding lint violation.

## Verification
- `uvx ruff check .` → All checks passed!
- `uvx --with torch pytest -q` → 24 passed

Import-sort only; no behavior change.

tests/test_pred_type.py

@@ -15,7 +15,7 @@ import pytest
 # Add project root to path for imports
 sys.path.insert(0, str(Path(__file__).parent.parent))
 
-from NRS.nodes_NRS import PredictionType, _RAW_TO_ENUM, NRS
+from NRS.nodes_NRS import _RAW_TO_ENUM, NRS, PredictionType
 
 
 def _make_model_sampling(class_name):