Adds balance assertion functionality to enable admins to verify accounting accuracy.
This includes:
- A new `balance_assertions` table in the database
- CRUD operations for balance assertions (create, get, list, check, delete)
- API endpoints for managing balance assertions (admin only)
- UI elements for creating, viewing, and re-checking assertions
Also, reorders the implementation roadmap in the documentation to reflect better the dependencies between phases.
Provides detailed documentation for the Castle Accounting extension, including architecture, transaction flows, balance calculation, API endpoints, and future improvements.
Documents design patterns inspired by Beancount, such as immutable data structures, plugin architecture, and balance assertions, with recommendations for adoption in the Castle extension.
Includes an implementation roadmap, security considerations, performance considerations, and a migration path for existing data.
