refactor: modernize code quality tooling with Ruff

- Replace black, isort, and flake8 with Ruff (all-in-one linter and formatter)
- Add comprehensive pyproject.toml configuration
- Simplify Makefile code quality targets
- Configure exclusions for venv/.venv in pyproject.toml
- Auto-fix 1,359 linting issues across codebase

Benefits:
- Much faster builds (Ruff is written in Rust)
- Single tool replaces multiple tools
- More comprehensive rule set (UP, B, C4, SIM, PIE, RET, Q)
- All configuration centralized in pyproject.toml
- Better import sorting and formatting consistency

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

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

models/schema/marketplace_product.py

@@ -1,6 +1,5 @@
 # models/schema/marketplace_products.py - Simplified validation
 from datetime import datetime
-from typing import List, Optional
 
 from pydantic import BaseModel, ConfigDict, Field
 
@@ -8,45 +7,45 @@ from models.schema.inventory import ProductInventorySummary
 
 
 class MarketplaceProductBase(BaseModel):
-    marketplace_product_id: Optional[str] = None
-    title: Optional[str] = None
-    description: Optional[str] = None
-    link: Optional[str] = None
-    image_link: Optional[str] = None
-    availability: Optional[str] = None
-    price: Optional[str] = None
-    brand: Optional[str] = None
-    gtin: Optional[str] = None
-    mpn: Optional[str] = None
-    condition: Optional[str] = None
-    adult: Optional[str] = None
-    multipack: Optional[int] = None
-    is_bundle: Optional[str] = None
-    age_group: Optional[str] = None
-    color: Optional[str] = None
-    gender: Optional[str] = None
-    material: Optional[str] = None
-    pattern: Optional[str] = None
-    size: Optional[str] = None
-    size_type: Optional[str] = None
-    size_system: Optional[str] = None
-    item_group_id: Optional[str] = None
-    google_product_category: Optional[str] = None
-    product_type: Optional[str] = None
-    custom_label_0: Optional[str] = None
-    custom_label_1: Optional[str] = None
-    custom_label_2: Optional[str] = None
-    custom_label_3: Optional[str] = None
-    custom_label_4: Optional[str] = None
-    additional_image_link: Optional[str] = None
-    sale_price: Optional[str] = None
-    unit_pricing_measure: Optional[str] = None
-    unit_pricing_base_measure: Optional[str] = None
-    identifier_exists: Optional[str] = None
-    shipping: Optional[str] = None
-    currency: Optional[str] = None
-    marketplace: Optional[str] = None
-    vendor_name: Optional[str] = None
+    marketplace_product_id: str | None = None
+    title: str | None = None
+    description: str | None = None
+    link: str | None = None
+    image_link: str | None = None
+    availability: str | None = None
+    price: str | None = None
+    brand: str | None = None
+    gtin: str | None = None
+    mpn: str | None = None
+    condition: str | None = None
+    adult: str | None = None
+    multipack: int | None = None
+    is_bundle: str | None = None
+    age_group: str | None = None
+    color: str | None = None
+    gender: str | None = None
+    material: str | None = None
+    pattern: str | None = None
+    size: str | None = None
+    size_type: str | None = None
+    size_system: str | None = None
+    item_group_id: str | None = None
+    google_product_category: str | None = None
+    product_type: str | None = None
+    custom_label_0: str | None = None
+    custom_label_1: str | None = None
+    custom_label_2: str | None = None
+    custom_label_3: str | None = None
+    custom_label_4: str | None = None
+    additional_image_link: str | None = None
+    sale_price: str | None = None
+    unit_pricing_measure: str | None = None
+    unit_pricing_base_measure: str | None = None
+    identifier_exists: str | None = None
+    shipping: str | None = None
+    currency: str | None = None
+    marketplace: str | None = None
+    vendor_name: str | None = None
 
 
 class MarketplaceProductCreate(MarketplaceProductBase):
@@ -70,7 +69,7 @@ class MarketplaceProductResponse(MarketplaceProductBase):
 
 
 class MarketplaceProductListResponse(BaseModel):
-    products: List[MarketplaceProductResponse]
+    products: list[MarketplaceProductResponse]
     total: int
     skip: int
     limit: int
@@ -78,4 +77,4 @@ class MarketplaceProductListResponse(BaseModel):
 
 class MarketplaceProductDetailResponse(BaseModel):
     product: MarketplaceProductResponse
-    inventory_info: Optional[ProductInventorySummary] = None
+    inventory_info: ProductInventorySummary | None = None