- Delete `Story` model implementation including `getVerbesStyle` method and related properties.
- Cleanup unused interfaces and redundant logic from the codebase.
- Implement `Content` model for converting Tiptap raw data into HTML and plain text.
- Add `Model` for storing and managing AI model configurations with pricing and metadata.
- Introduce `Story` model to handle verbal styles and linguistic properties for diverse narrative structures.
- Update `book.repository.ts` to refine `updateBookBasicInformation` and `insertNewPlotPoint` methods, removing unused parameters and optimizing queries.
