- Reorganized utility modules from `src/utils` to `src/lib` for clearer separation of concerns.
- Introduced new, dedicated type definitions in `src/types` for improved type safety in configuration and TTS API interactions.
- Replaced `src/types/appConfig.ts` with `src/types/config.ts`.
- Added `src/types/tts.ts` for TTS request payloads, error structures, and retry options.
- Updated module imports across several contexts (`Config`, `EPUB`, `HTML`, `PDF`, `TTS`) and components to reflect the new `lib` and `types` locations.
- Enhanced TTS API request and error handling in `src/app/api/tts/route.ts` and TTS-consuming contexts with explicit types.
- Simplified `ProgressCard`, `ProgressPopup`, and `AudiobookExportModal` components by removing the `isProcessing` prop, centralizing processing state management.
- Streamlined `HTMLContext` by removing `createFullAudioBook` and `isAudioCombining` properties, focusing its scope.
- Offload computationally intensive text matching for real-time highlighting to a dedicated Web Worker, ensuring the main thread remains responsive during playback.
- Implement a new overlay-based highlighting system that renders independently of the PDF's text layer, providing smoother and more reliable visual feedback without interfering with document rendering.
- Introduce a new setting allowing users to enable or disable real-time text highlighting in PDFs, offering personalized control over the reading interface.
- Upgrade the underlying text comparison algorithm to Dice similarity for more accurate and context-aware matching of spoken words to on-screen text, improving synchronization precision.
- Improve sentence boundary detection, especially for quoted dialogue and complex structures, by enhancing the NLP processing logic, leading to a more natural audio-text flow.
