Function detect_exchange_compaction_request 

pub fn detect_exchange_compaction_request(diff: &str) -> bool

Detect whether the user explicitly requested exchange compaction in added diff lines.

This only matches direct imperative forms that start with compact exchange (or compact the exchange) after prompt/pending normalization, and only when authored as exchange prose — a queue/backlog/review list item that merely begins with those words is a task entry, not a same-turn directive, and is skipped (#qcompactfp).