Function decode_chain 

pub fn decode_chain(input: &str) -> String

Apply the full decode chain: percent → HTML → base64 → Unicode NFKC.

Each layer is best-effort:

• percent and HTML decoding pass non-matching bytes through unchanged
• base64 decoding requires the entire input to be a valid base64 token; otherwise the layer returns the input unchanged (no partial decode)
• NFKC always succeeds

Examples

use agentsec_core::paste::obfuscation::decode_chain;

// Plain text passes through.
assert_eq!(decode_chain("hello"), "hello");

// Percent-encoded text is decoded.
assert_eq!(decode_chain("hello%20world"), "hello world");