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>

models/schema/inventory.py

@@ -1,6 +1,7 @@
 # models/schema/inventory.py
 from datetime import datetime
 from typing import List, Optional
+
 from pydantic import BaseModel, ConfigDict, Field
 
 
@@ -11,16 +12,21 @@ class InventoryBase(BaseModel):
 
 class InventoryCreate(InventoryBase):
     """Set exact inventory quantity (replaces existing)."""
+
     quantity: int = Field(..., description="Exact inventory quantity", ge=0)
 
 
 class InventoryAdjust(InventoryBase):
     """Add or remove inventory quantity."""
-    quantity: int = Field(..., description="Quantity to add (positive) or remove (negative)")
+
+    quantity: int = Field(
+        ..., description="Quantity to add (positive) or remove (negative)"
+    )
 
 
 class InventoryUpdate(BaseModel):
     """Update inventory fields."""
+
     quantity: Optional[int] = Field(None, ge=0)
     reserved_quantity: Optional[int] = Field(None, ge=0)
     location: Optional[str] = None
@@ -28,6 +34,7 @@ class InventoryUpdate(BaseModel):
 
 class InventoryReserve(BaseModel):
     """Reserve inventory for orders."""
+
     product_id: int
     location: str
     quantity: int = Field(..., gt=0)
@@ -60,6 +67,7 @@ class InventoryLocationResponse(BaseModel):
 
 class ProductInventorySummary(BaseModel):
     """Inventory summary for a product."""
+
     product_id: int
     vendor_id: int
     product_sku: Optional[str]