- Introduce `BooksSyncContext` for managing book synchronization states (server-only, local-only, to-sync, etc.).
- Remove `UserContext` and related dependencies.
- Refine localization strings (`en.json`) with sync-related updates (e.g., "toSyncFromServer", "toSyncToServer").
- Extend database schema with additional tables and fields for syncing books, chapters, and related entities.
- Add `last_update` fields and update corresponding repository methods to support synchronization logic.
- Enhance IPC handlers with stricter typing, data validation, and sync-aware operations.
- Increment `SCHEMA_VERSION` to 2 in `schema.ts`.
- Remove all `meta_*` columns from database tables.
- Add migration logic to handle schema upgrades and clean up unused columns.
- Modify database models and repository methods to exclude `meta_*` fields for stricter typings and improved structure.
- Refactor and optimize query statements across repositories to align with new schema changes.
- Replace absolute import paths with relative paths for consistency across files.
- Transition database operations in Electron main process to modular handlers in `ipc/book.ipc.ts` using the `createHandler` pattern.
- Update database sync service to use `window.electron.invoke()` for improved reliability and structure.
- Refactor `AddNewBookForm` to handle both online and offline book creation seamlessly.
- 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.
