- Updated `getCurrentSubscription` and related functions to reflect terminology changes.
- Adjusted subscription levels and access checks to streamline logic.
- Removed unused cases in `getSubLevel` and optimized conditionals for clarity.
- Deleted redundant components (`AddActionButton`, `AlertBox`, `AlertStack`, `BackButton`, `CancelButton`, and `CollapsableArea`) and related files.
- Removed unused models (`Book`, `BookSerie`, `BookTables`, `Character`, and `Chapter`) to reduce codebase clutter.
- Updated project structure and references to reflect these removals.