Replace Batch with VendorLot and StockLot, add CLAUDE.md

[therealmoronto]

What has been implemented

• Replaced "Batch" concept with new "VendorLot" and "StockLot" entities in the project.
• Updated related models, controllers, and mappers to reflect the new entities.
• Applied database schema changes to support the new structure using migration.
• Added comprehensive tests to ensure integrity of the updates.
• Added CLAUDE.md, detailing the updated architecture, commands, and development guidelines.

Checklist

• Tests have been written or updated.
• Documentation has been updated where applicable.
• Migration steps are noted, and the migration script is included.