feat(#10): add batch download settings and capabilities

- Introduced new batch download settings in the settings slice, allowing users to configure options for directory picking, streaming ZIP downloads, and blob ZIP downloads.
- Implemented a new general settings panel for managing batch download preferences.
- Added utility functions to handle directory selection and ZIP file creation.
- Updated the download logic to support multiple download modes based on user preferences.
- Enhanced documentation to reflect changes in batch download functionality.

package.json

@@ -20,6 +20,8 @@
     "@reduxjs/toolkit": "^2.9.0",
     "@unlock-music/crypto": "^0.1.12",
     "classnames": "^2.5.1",
+    "fflate": "^0.8.3",
+    "idb-keyval": "^6.3.0",
     "nanoid": "^5.1.6",
     "radash": "^12.1.1",
     "react": "^19.2.0",