Now implements streaming download+decryption entirely in Rust:
- Added reqwest/tokio/futures-util dependencies
- Created StreamingDecryptor for chunk-by-chunk decryption
- New download_and_decrypt_track command streams to disk directly
- Frontend simplified to single invoke() call
The JavaScript blowfish-node library had a critical bug where it would
sometimes return 2047 bytes instead of 2048 during decryption, causing
byte alignment issues that corrupted FLAC audio at specific intervals
(~every 32/82 seconds).
Changes:
- Add Rust dependencies: blowfish, md5, byteorder
- Implement new module in Rust with proper Blowfish CBC
- Add decryption Tauri command
- Update frontend to call Rust decryption instead of JavaScript
- Remove buggy JavaScript blowfish implementation
- Update decryption algorithm (6144-byte windows)
