Function redact 

pub fn redact(input: &[u8]) -> RedactionOutcome

Scans input (treated as best-effort UTF-8 via lossy conversion) for known secret shapes and replaces each match with a marker identifying the kind of secret found. Returns the redacted bytes plus a count of total replacements made.

This is a best-effort safety net, not a strict parser: invalid UTF-8 in input is handled via String::from_utf8_lossy, which substitutes the standard replacement character for any invalid byte sequences before the patterns below are applied.