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/workflows/test_integration.py

@@ -33,12 +33,15 @@ class TestIntegrationFlows:
             "quantity": 50,
         }
 
-        response = client.post("/api/v1/inventory", headers=auth_headers, json=inventory_data)
+        response = client.post(
+            "/api/v1/inventory", headers=auth_headers, json=inventory_data
+        )
         assert response.status_code == 200
 
         # 3. Get product with inventory info
         response = client.get(
-            f"/api/v1/marketplace/product/{product['marketplace_product_id']}", headers=auth_headers
+            f"/api/v1/marketplace/product/{product['marketplace_product_id']}",
+            headers=auth_headers,
         )
         assert response.status_code == 200
         product_detail = response.json()
@@ -55,14 +58,15 @@ class TestIntegrationFlows:
 
         # 5. Search for product
         response = client.get(
-            "/api/v1/marketplace/product?search=Updated Integration", headers=auth_headers
+            "/api/v1/marketplace/product?search=Updated Integration",
+            headers=auth_headers,
         )
         assert response.status_code == 200
         assert response.json()["total"] == 1
 
     def test_product_workflow(self, client, auth_headers):
         """Test vendor creation and product management workflow"""
-        # 1. Create a vendor 
+        # 1. Create a vendor
         vendor_data = {
             "vendor_code": "FLOWVENDOR",
             "name": "Integration Flow Vendor",
@@ -91,7 +95,9 @@ class TestIntegrationFlows:
         # This would test the vendor -product association
 
         # 4. Get vendor details
-        response = client.get(f"/api/v1/vendor/{vendor ['vendor_code']}", headers=auth_headers)
+        response = client.get(
+            f"/api/v1/vendor/{vendor ['vendor_code']}", headers=auth_headers
+        )
         assert response.status_code == 200
 
     def test_inventory_operations_workflow(self, client, auth_headers):