- 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.