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/product.py

@@ -1,6 +1,5 @@
 # models/schema/product.py
 from datetime import datetime
-from typing import List, Optional
 
 from pydantic import BaseModel, ConfigDict, Field
 
@@ -12,30 +11,30 @@ class ProductCreate(BaseModel):
     marketplace_product_id: int = Field(
         ..., description="MarketplaceProduct ID to add to vendor catalog"
     )
-    product_id: Optional[str] = Field(
+    product_id: str | None = Field(
         None, description="Vendor's internal SKU/product ID"
     )
-    price: Optional[float] = Field(None, ge=0)
-    sale_price: Optional[float] = Field(None, ge=0)
-    currency: Optional[str] = None
-    availability: Optional[str] = None
-    condition: Optional[str] = None
+    price: float | None = Field(None, ge=0)
+    sale_price: float | None = Field(None, ge=0)
+    currency: str | None = None
+    availability: str | None = None
+    condition: str | None = None
     is_featured: bool = False
     min_quantity: int = Field(1, ge=1)
-    max_quantity: Optional[int] = Field(None, ge=1)
+    max_quantity: int | None = Field(None, ge=1)
 
 
 class ProductUpdate(BaseModel):
-    product_id: Optional[str] = None
-    price: Optional[float] = Field(None, ge=0)
-    sale_price: Optional[float] = Field(None, ge=0)
-    currency: Optional[str] = None
-    availability: Optional[str] = None
-    condition: Optional[str] = None
-    is_featured: Optional[bool] = None
-    is_active: Optional[bool] = None
-    min_quantity: Optional[int] = Field(None, ge=1)
-    max_quantity: Optional[int] = Field(None, ge=1)
+    product_id: str | None = None
+    price: float | None = Field(None, ge=0)
+    sale_price: float | None = Field(None, ge=0)
+    currency: str | None = None
+    availability: str | None = None
+    condition: str | None = None
+    is_featured: bool | None = None
+    is_active: bool | None = None
+    min_quantity: int | None = Field(None, ge=1)
+    max_quantity: int | None = Field(None, ge=1)
 
 
 class ProductResponse(BaseModel):
@@ -44,33 +43,33 @@ class ProductResponse(BaseModel):
     id: int
     vendor_id: int
     marketplace_product: MarketplaceProductResponse
-    product_id: Optional[str]
-    price: Optional[float]
-    sale_price: Optional[float]
-    currency: Optional[str]
-    availability: Optional[str]
-    condition: Optional[str]
+    product_id: str | None
+    price: float | None
+    sale_price: float | None
+    currency: str | None
+    availability: str | None
+    condition: str | None
     is_featured: bool
     is_active: bool
     display_order: int
     min_quantity: int
-    max_quantity: Optional[int]
+    max_quantity: int | None
     created_at: datetime
     updated_at: datetime
 
     # Include inventory summary
-    total_inventory: Optional[int] = None
-    available_inventory: Optional[int] = None
+    total_inventory: int | None = None
+    available_inventory: int | None = None
 
 
 class ProductDetailResponse(ProductResponse):
     """Product with full inventory details."""
 
-    inventory_locations: List[InventoryLocationResponse] = []
+    inventory_locations: list[InventoryLocationResponse] = []
 
 
 class ProductListResponse(BaseModel):
-    products: List[ProductResponse]
+    products: list[ProductResponse]
     total: int
     skip: int
     limit: int