Add 'force-dynamic' export to audiobook and documents API routes to ensure
dynamic rendering. Remove 'nodejs' runtime export from TTS route for consistency.
Abstracted direct fetch calls across components and contexts into new functions within `src/lib/client.ts`. This provides a consistent and centralized interface for interacting with backend APIs.
- Introduced `src/lib/client.ts` to encapsulate API request logic.
- Standardized audio buffer types (`TTSAudioBuffer`, `TTSAudioBytes`) in `src/types/tts.ts`.
- Moved client-specific request types (`TTSRequestPayload`, `TTSRequestHeaders`, `TTSRetryOptions`) to `src/types/client.ts`.
- Updated API routes and consumer components/contexts to leverage the new client library functions and type definitions.
- Removed `src/utils/audio.ts` as its utility functions are now part of `src/lib/client.ts`.
- Relocated all audiobook-related API routes from `/api/audio/convert/*` to `/api/audiobook/*`.
- This change affects endpoints for chapter conversion, retrieval, deletion, and overall audiobook status.
- Updated client-side calls in `AudiobookExportModal.tsx`, `EPUBContext.tsx`, and `PDFContext.tsx` to reflect the new API paths.
- Modified API tests (`api.spec.ts`, `export.spec.ts`) to target the restructured endpoints.
- The new API structure provides better organization and a clearer, more consistent interface for audiobook functionality.