Background chats teach compaction what to keep
When a background chat reads back a file its summary left out, Bandicot now learns from it, just as it does for the open chat.
After a chat compacts, Bandicot watches whether the work later needs something it set aside, and uses that to choose better next time. It only watched the chat open in the window, so lessons from chats working in the background were lost.
Now every chat's turns count, wherever it runs.