Function decompress_body 

pub fn decompress_body(
    header: Option<&str>,
    body: Bytes,
) -> Result<Bytes, ErrorMessage>

Decompresses the body based on the Content-Encoding header.

Supports gzip, deflate, snappy, zstd, and identity (no compression).

Caps the decompressed output at 100 MiB to mitigate decompression-bomb DoS attacks.