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/unit/services/test_stats_service.py

@@ -2,8 +2,8 @@
 import pytest
 
 from app.services.stats_service import StatsService
-from models.database.marketplace_product import MarketplaceProduct
 from models.database.inventory import Inventory
+from models.database.marketplace_product import MarketplaceProduct
 
 
 @pytest.mark.unit
@@ -15,7 +15,9 @@ class TestStatsService:
         """Setup method following the same pattern as other service tests"""
         self.service = StatsService()
 
-    def test_get_comprehensive_stats_basic(self, db, test_marketplace_product, test_inventory):
+    def test_get_comprehensive_stats_basic(
+        self, db, test_marketplace_product, test_inventory
+    ):
         """Test getting comprehensive stats with basic data"""
         stats = self.service.get_comprehensive_stats(db)
 
@@ -31,7 +33,9 @@ class TestStatsService:
         assert stats["total_inventory_entries"] >= 1
         assert stats["total_inventory_quantity"] >= 10  # test_inventory has quantity 10
 
-    def test_get_comprehensive_stats_multiple_products(self, db, test_marketplace_product):
+    def test_get_comprehensive_stats_multiple_products(
+        self, db, test_marketplace_product
+    ):
         """Test comprehensive stats with multiple products across different dimensions"""
         # Create products with different brands, categories, marketplaces
         additional_products = [
@@ -87,7 +91,7 @@ class TestStatsService:
                 brand=None,  # Null brand
                 google_product_category=None,  # Null category
                 marketplace=None,  # Null marketplace
-                vendor_name=None,  # Null vendor 
+                vendor_name=None,  # Null vendor
                 price="10.00",
                 currency="EUR",
             ),
@@ -97,7 +101,7 @@ class TestStatsService:
                 brand="",  # Empty brand
                 google_product_category="",  # Empty category
                 marketplace="",  # Empty marketplace
-                vendor_name="",  # Empty vendor 
+                vendor_name="",  # Empty vendor
                 price="15.00",
                 currency="EUR",
             ),
@@ -124,7 +128,11 @@ class TestStatsService:
 
         # Find our test marketplace in the results
         test_marketplace_stat = next(
-            (stat for stat in stats if stat["marketplace"] == test_marketplace_product.marketplace),
+            (
+                stat
+                for stat in stats
+                if stat["marketplace"] == test_marketplace_product.marketplace
+            ),
             None,
         )
         assert test_marketplace_stat is not None
@@ -309,7 +317,9 @@ class TestStatsService:
 
         count = self.service._get_unique_marketplaces_count(db)
 
-        assert count >= 2  # At least Amazon and eBay, plus test_marketplace_product marketplace
+        assert (
+            count >= 2
+        )  # At least Amazon and eBay, plus test_marketplace_product marketplace
         assert isinstance(count, int)
 
     def test_get_unique_vendors_count(self, db, test_marketplace_product):
@@ -338,7 +348,9 @@ class TestStatsService:
 
         count = self.service._get_unique_vendors_count(db)
 
-        assert count >= 2  # At least VendorA and VendorB, plus test_marketplace_product vendor
+        assert (
+            count >= 2
+        )  # At least VendorA and VendorB, plus test_marketplace_product vendor
         assert isinstance(count, int)
 
     def test_get_inventory_statistics(self, db, test_inventory):
@@ -438,7 +450,7 @@ class TestStatsService:
         db.add_all(marketplace_products)
         db.commit()
 
-        vendors =self.service._get_vendors_by_marketplace(db, "TestMarketplace")
+        vendors = self.service._get_vendors_by_marketplace(db, "TestMarketplace")
 
         assert len(vendors) == 2
         assert "TestVendor1" in vendors
@@ -482,7 +494,9 @@ class TestStatsService:
 
     def test_get_products_by_marketplace_not_found(self, db):
         """Test getting product count for non-existent marketplace"""
-        count = self.service._get_products_by_marketplace_count(db, "NonExistentMarketplace")
+        count = self.service._get_products_by_marketplace_count(
+            db, "NonExistentMarketplace"
+        )
 
         assert count == 0