Add initial project structure and tests for Elytra PIM Client

- Created pyproject.toml for project metadata and dependencies.
- Added requirements.txt for development and production dependencies.
- Implemented basic test structure in the tests module.
- Developed unit tests for ElytraClient, including Pydantic validation and error handling.

examples/__init__.py

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+"""Examples module for Elytra PIM Client"""

examples/basic_usage.py

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+"""Example usage of the Elytra PIM Client with Pydantic validation"""
+
+from dotenv import load_dotenv
+from elytra_client import (
+    ElytraClient,
+    SingleProductResponse,
+    SingleNewProductRequestBody,
+    AttributeRequestBody,
+)
+from elytra_client.config import ElytraConfig
+
+# Load environment variables from .env file
+load_dotenv()
+
+
+def fetch_products_example(client):
+    """Example showing product fetching with Pydantic validation"""
+    print("\n--- Fetching Products with Pydantic Validation ---")
+    products_response = client.get_products(lang="en", page=1, limit=3)
+    
+    print(f"Total products: {products_response.get('total')}")
+    print(f"Current page: {products_response.get('page')}")
+    
+    # Items are Pydantic validated models with full type hints
+    if products_response.get("items"):
+        for product in products_response["items"]:
+            assert isinstance(product, SingleProductResponse)
+            print(f"  - {product.productName} (ID: {product.id})")
+
+
+def fetch_single_product_example(client):
+    """Example showing single product fetch with direct Pydantic model"""
+    print("\n--- Fetching Single Product ---")
+    try:
+        product: SingleProductResponse = client.get_product(123, lang="en")
+        print(f"Product Name: {product.productName}")
+        print(f"Status: {product.objectStatus}")
+        print(f"Created: {product.created}")
+        
+        if product.attributes:
+            print(f"Attributes: {len(product.attributes)}")
+            for attr in product.attributes:
+                print(f"  - {attr.attributeName}: {attr.value}")
+    except Exception as e:
+        print(f"Product not found or error: {e}")
+
+
+def create_product_example(client):
+    """Example showing product creation with Pydantic validation"""
+    print("\n--- Creating Product with Pydantic Validation ---")
+    try:
+        # Create with Pydantic model - validation happens automatically
+        new_product = SingleNewProductRequestBody(
+            productName="EXAMPLE-PRODUCT-001",
+            parentId=1,
+            attributeGroupId=10,
+            attributes=[
+                AttributeRequestBody(
+                    attributeId=1,
+                    value="Sample Value",
+                    languageCode="en"
+                )
+            ]
+        )
+        
+        # Create product - returns validated Pydantic model
+        created: SingleProductResponse = client.create_product(new_product)
+        print(f"✅ Product created successfully!")
+        print(f"  ID: {created.id}")
+        print(f"  Name: {created.productName}")
+    except Exception as e:
+        print(f"❌ Error: {e}")
+
+
+def validate_data_example():
+    """Example showing Pydantic validation"""
+    print("\n--- Pydantic Validation Example ---")
+    try:
+        # This will validate the data
+        product = SingleNewProductRequestBody(
+            productName="VALID-PRODUCT",
+            parentId=1,
+            attributeGroupId=10
+        )
+        print("✅ Valid product data")
+        print(f"  Data: {product.model_dump()}")
+    except Exception as e:
+        print(f"❌ Validation failed: {e}")
+
+
+def main():
+    """Main example demonstrating Pydantic-driven Elytra client"""
+    try:
+        # Load configuration from environment
+        config = ElytraConfig.from_env()
+
+        # Create client with context manager
+        with ElytraClient(base_url=config.base_url, api_key=config.api_key) as client:
+            print("✅ Connected to Elytra PIM API")
+            print("   Using Pydantic v2 for data validation\n")
+
+            # Run examples
+            validate_data_example()
+            fetch_products_example(client)
+            fetch_single_product_example(client)
+            create_product_example(client)
+
+            print("\n✅ All examples completed successfully!")
+
+    except Exception as e:
+        print(f"❌ Error: {e}")
+
+
+if __name__ == "__main__":
+    main()