- Introduced a new permission model with `PermissionGroup`, `UserPermissionOverride`, and `HiddenEntity` to manage access control.
- Added `DBPermissionsHandler` for handling permission-related database operations.
- Updated `User` model to include a foreign key to `PermissionGroup` and modified `oauth_scopes` to derive from the new permission model.
- Implemented tests to ensure the new permission model maintains parity with legacy access controls.
- Created documentation outlining the new permission system architecture and migration strategy.
