rate: a desk row offers only the buttons that start from its state

The first desk score offered every button of the bucket, where portal
shows a row only the moves from its own state; that scored the live
vel 17 of 26 and sent a rewrite of the neighbour-help desk chasing an
instrument fault. With the row's buttons only: 24 of 26, and the
rewrite loses on the fair test too. Noted: an accent-stripped state id
(ikke_lost) reads as English even to a strong picker.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

src/rate.rs

@@ -307,19 +307,30 @@ pub fn rate(argv: &[String]) -> anyhow::Result<()> {
     if !desks.is_empty() {
         println!("{:<20} {:<24} {:>8}   {}", "desk", "bucket", "buttons", "mistaken for");
         for (page, group, bucket, moves) in &desks {
-            let labels: Vec<&str> = moves.iter().map(|(_, _, l)| l.as_str()).collect();
+            // A desk row shows only the buttons that start from the
+            // row's state, so those are the ones the worker chooses
+            // among; a state with one button has nothing to confuse.
             let mut right = 0;
+            let mut asked = 0;
             let mut mistaken = Vec::new();
             for (i, (from, to, label)) in moves.iter().enumerate() {
+                let labels: Vec<&str> = moves.iter().filter(|(f, _, _)| f == from).map(|(_, _, l)| l.as_str()).collect();
+                if labels.len() < 2 {
+                    continue;
+                }
+                asked += 1;
                 let picked = button_pick(&cmd, group, bucket, from, to, &labels, i)?;
                 if picked == *label {
                     right += 1;
                 } else {
-                    mistaken.push(format!("{to} as {picked:?}"));
+                    mistaken.push(format!("{from}>{to} as {picked:?}"));
                 }
             }
-            println!("{:<20} {:<24} {:>3} of {:<2}   {}", page, bucket, right, moves.len(), mistaken.join("; "));
-            report.insert(format!("desk {page} {bucket}"), json!({ "right": right, "of": moves.len(), "mistaken": mistaken }));
+            if asked == 0 {
+                continue;
+            }
+            println!("{:<20} {:<24} {:>3} of {:<2}   {}", page, bucket, right, asked, mistaken.join("; "));
+            report.insert(format!("desk {page} {bucket}"), json!({ "right": right, "of": asked, "mistaken": mistaken }));
         }
         println!();
     }