fix: use rust blowfish instead of node

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)

src-tauri/Cargo.toml

@@ -30,4 +30,7 @@ tauri-plugin-sql = { version = "2", features = ["sqlite"] }
 id3 = "1.16.3"
 metaflac = "0.2.8"
 tauri-plugin-process = "2"
+blowfish = "0.9"
+md5 = "0.7"
+byteorder = "1.5.0"