Function process_mime_body 

pub fn process_mime_body(
    headers: &[(String, String)],
    body_raw: &[u8],
) -> (String, Option<String>)

Processes a MIME message body, returning decoded text and detected charset.

Handles multipart messages, inline images, attachments, and charset detection.

Security

Only safe image MIME types are embedded inline; SVG is excluded due to script risks.