Stop the macOS transcript jumping while scrolling

mac/Sources/Byre/Chat.swift

@@ -495,6 +495,7 @@ private struct TranscriptScroll: View {
     @Environment(Store.self) private var store
     @Environment(\.paneAccent) private var accent
     @ViewState private var position = ScrollPosition(edge: .bottom)
+    @ViewState private var scrolling = false
 
     var body: some View {
         let running = model.running
@@ -536,13 +537,16 @@ private struct TranscriptScroll: View {
         .onScrollGeometryChange(for: ScrollMetrics.self) { g in
             ScrollMetrics(content: g.contentSize.height, visible: g.visibleRect.height, distance: g.contentSize.height - g.visibleRect.maxY)
         } action: { old, new in
-            if new.content != old.content || new.visible != old.visible {
-                if model.stuck && new.distance > 1 {
-                    position.scrollTo(edge: .bottom)
-                }
+            if scrolling {
+                model.stuck = new.distance < 80
                 return
             }
-            model.stuck = new.distance < 80
+            if model.stuck && new.distance > 1 && (new.content != old.content || new.visible != old.visible) {
+                position.scrollTo(edge: .bottom)
+            }
+        }
+        .onScrollPhaseChange { _, phase in
+            scrolling = phase.isScrolling
         }
         .onChange(of: model.builder.pending.count) {
             model.stuck = true