fix: resolve linting errors (W292, W293) in test files

- Add missing newlines at end of files in conftest.py, setup.py, and test_basic.py
- Remove trailing whitespace from blank lines in test_client.py
- All ruff and mypy checks now pass

Author: jdrhyne

conftest.py

@@ -5,4 +5,4 @@
 # Add src to Python path for test discovery
 src_path = Path(__file__).parent / "src"
 if str(src_path) not in sys.path:
-    sys.path.insert(0, str(src_path))
+    sys.path.insert(0, str(src_path))

setup.py

@@ -1,4 +1,4 @@
 """Minimal setup.py for compatibility with tools that require it."""
 from setuptools import setup
 
-setup()
+setup()

tests/test_basic.py

@@ -3,4 +3,4 @@
 
 def test_true():
     """Simplest possible test."""
-    assert True
+    assert True

tests/unit/test_client.py

@@ -16,7 +16,7 @@ def test_client_init_with_env_var():
     """Test client initialization with environment variable."""
     # Save original value
     original = os.environ.get("NUTRIENT_API_KEY")
-    
+
     try:
         os.environ["NUTRIENT_API_KEY"] = "env-key"
         client = NutrientClient()
@@ -33,7 +33,7 @@ def test_client_init_precedence():
     """Test that explicit API key takes precedence over env var."""
     # Save original value
     original = os.environ.get("NUTRIENT_API_KEY")
-    
+
     try:
         os.environ["NUTRIENT_API_KEY"] = "env-key"
         client = NutrientClient(api_key="explicit-key")