Hide duplicate snapshot lines and the turn-end line before a snapshot

mac/Sources/Byre/Chat.swift

@@ -1133,7 +1133,14 @@ struct RowView: View {
 
     var body: some View {
         if !row.hidden {
-            content
+            if let seq = row.summarySeq {
+                content
+                    .onScrollVisibilityChange(threshold: 0.01) { visible in
+                        model.summaryVisible(seq, visible)
+                    }
+            } else {
+                content
+            }
         }
     }
 
@@ -1267,19 +1274,12 @@ struct RowView: View {
             PreBox(text: text)
 
         case .turnEnd(let error):
-            Group {
-                if let error {
-                    Text(error)
-                        .font(Fonts.font(11))
-                        .foregroundStyle(Palette.danger)
-                } else {
-                    Rectangle().fill(Palette.border).frame(height: 1)
-                }
-            }
-            .onScrollVisibilityChange(threshold: 0.01) { visible in
-                if let seq = row.summarySeq {
-                    model.summaryVisible(seq, visible)
-                }
+            if let error {
+                Text(error)
+                    .font(Fonts.font(11))
+                    .foregroundStyle(Palette.danger)
+            } else {
+                Rectangle().fill(Palette.border).frame(height: 1)
             }
 
         case .note(let note):

mac/Sources/Byre/TranscriptBuilder.swift

@@ -518,11 +518,21 @@ final class TranscriptBuilder {
             if ev.kind == "snapshot.created" {
                 ctx.run = nil
                 let snap = try! decodePayload(ev.payload, as: Snapshot.self)
-                let row = Row(.snapshot(snap), taskId: rowTask)
-                ctx.snapshots[snapKey(snap.n)] = row
                 if ![.answer, .fork, .askHuman].contains(snap.trigger) && sink == nil && own {
                     lastReady = nil
                 }
+                release()
+                let prev = (ctx.handoff?.body ?? sink ?? root).rows.last { !$0.hidden }
+                if let prev, case .snapshot(let p) = prev.kind, p.treeSha == snap.treeSha, prev.taskId == rowTask {
+                    ctx.snapshots[snapKey(snap.n)] = prev
+                    continue
+                }
+                let row = Row(.snapshot(snap), taskId: rowTask)
+                ctx.snapshots[snapKey(snap.n)] = row
+                if let prev, case .turnEnd(nil) = prev.kind {
+                    prev.hidden = true
+                    row.summarySeq = prev.summarySeq
+                }
                 put(row)
                 continue
             }