style: apply black and isort formatting across entire codebase

- Standardize quote style (single to double quotes)
- Reorder and group imports alphabetically
- Fix line breaks and indentation for consistency
- Apply PEP 8 formatting standards

Also updated Makefile to exclude both venv and .venv from code quality checks.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

tests/integration/security/test_input_validation.py

@@ -11,7 +11,8 @@ class TestInputValidation:
         malicious_search = "'; DROP TABLE products; --"
 
         response = client.get(
-            f"/api/v1/marketplace/product?search={malicious_search}", headers=auth_headers
+            f"/api/v1/marketplace/product?search={malicious_search}",
+            headers=auth_headers,
         )
 
         # Should not crash and should return normal response
@@ -40,17 +41,23 @@ class TestInputValidation:
     def test_parameter_validation(self, client, auth_headers):
         """Test parameter validation for API endpoints"""
         # Test invalid pagination parameters
-        response = client.get("/api/v1/marketplace/product?limit=-1", headers=auth_headers)
+        response = client.get(
+            "/api/v1/marketplace/product?limit=-1", headers=auth_headers
+        )
         assert response.status_code == 422  # Validation error
 
-        response = client.get("/api/v1/marketplace/product?skip=-1", headers=auth_headers)
+        response = client.get(
+            "/api/v1/marketplace/product?skip=-1", headers=auth_headers
+        )
         assert response.status_code == 422  # Validation error
 
     def test_json_validation(self, client, auth_headers):
         """Test JSON validation for POST requests"""
         # Test invalid JSON structure
         response = client.post(
-            "/api/v1/marketplace/product", headers=auth_headers, content="invalid json content"
+            "/api/v1/marketplace/product",
+            headers=auth_headers,
+            content="invalid json content",
         )
         assert response.status_code == 422  # JSON decode error
 
@@ -58,6 +65,8 @@ class TestInputValidation:
         response = client.post(
             "/api/v1/marketplace/product",
             headers=auth_headers,
-            json={"title": "Test MarketplaceProduct"},  # Missing required marketplace_product_id
+            json={
+                "title": "Test MarketplaceProduct"
+            },  # Missing required marketplace_product_id
         )
         assert response.status_code == 422  # Validation error