[tests] Added test_niah_standalone.py.

nanovllm/models/__init__.py

@@ -3,7 +3,13 @@
 from nanovllm.models.registry import register_model, get_model_class, MODEL_REGISTRY
 
 # Import models to trigger registration
-from nanovllm.models import qwen3
+# Qwen3 requires transformers>=4.51.0 for Qwen3Config
+try:
+    from nanovllm.models import qwen3
+except ImportError as e:
+    import warnings
+    warnings.warn(f"Qwen3 model not available (requires transformers>=4.51.0): {e}")
+
 from nanovllm.models import llama
 
 __all__ = ["register_model", "get_model_class", "MODEL_REGISTRY"]