feat: Revamp EPUB import process with batch upload support and enhanced API integration

- Introduced a new batch import client for handling multiple EPUB files simultaneously.
- Updated API routes for previewing and importing EPUB files, improving error handling and response management.
- Enhanced genre management during import, allowing for dynamic creation and association of genres.
- Implemented long-fetch handling to accommodate lengthy processing times for large EPUB files.
- Refined UI components for better user experience in the import workflow.

package.json

@@ -64,6 +64,7 @@
     "recharts": "2.15.0",
     "sonner": "^1.7.1",
     "tailwind-merge": "^3.3.1",
+    "undici": "^8.2.0",
     "vaul": "^1.1.2",
     "zod": "^3.24.1"
   },