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>

app/api/v1/__init__.py

@@ -3,6 +3,6 @@
 API Version 1 - All endpoints
 """
 
-from . import admin, vendor, shop
+from . import admin, shop, vendor
 
-__all__ = ["admin", "vendor", "shop"]
+__all__ = ["admin", "vendor", "shop"]