Function parse_save_file 

pub fn parse_save_file(path: &Path) -> Result<SaveRoot, SaveError>

Parse a save file from disk, handling the full pipeline.

Runs the complete parsing pipeline:

1. Read raw bytes from disk
2. Decompress LZ4 blocks (passes through plaintext JSON unchanged)
3. Check for obfuscated keys and deobfuscate if needed
4. Deserialize into SaveRoot

This is the high-level entry point for reading NMS save files. For already-decompressed, already-deobfuscated JSON bytes, use parse_save instead.