Function decompress 

pub fn decompress(input: &[u8], config: &EngineConfiguration) -> Result<Vec<u8>>

Decompress a CRSH-format byte slice.

Reads the file footer first, loads the index, then decompresses all blocks in parallel.

Errors

• VersionMismatch — file was produced by a different engine version.
• InvalidFormat — magic bytes invalid or file truncated.
• ChecksumMismatch — a block’s CRC32 does not match.
• ExpansionLimitExceeded — output would exceed config.max_decompression_ratio.
• IndexCorrupted — block index is missing or truncated.
• Cancelled — cancelled via progress callback.