fix(chat-ui): avoid animated initial scroll

apps/shared/ClawdisKit/Sources/ClawdisChatUI/ChatView.swift

@@ -10,6 +10,7 @@ public struct ClawdisChatView: View {
     @State private var viewModel: ClawdisChatViewModel
     @State private var scrollerBottomID = UUID()
     @State private var showSessions = false
+    @State private var hasPerformedInitialScroll = false
     private let showsSessionSwitcher: Bool
     private let style: Style
 
@@ -67,6 +68,7 @@ public struct ClawdisChatView: View {
 
     private var messageList: some View {
         ScrollViewReader { proxy in
+            ZStack {
                 ScrollView {
                     LazyVStack(spacing: Layout.messageSpacing) {
                         ForEach(self.visibleMessages) { msg in
@@ -99,12 +101,26 @@ public struct ClawdisChatView: View {
                     .padding(.bottom, Layout.messageListPaddingBottom)
                     .padding(.horizontal, Layout.messageListPaddingHorizontal)
                 }
+
+                if self.viewModel.isLoading {
+                    ProgressView()
+                        .controlSize(.large)
+                        .frame(maxWidth: .infinity, maxHeight: .infinity)
+                }
+            }
+            .onChange(of: self.viewModel.isLoading) { _, isLoading in
+                guard !isLoading, !self.hasPerformedInitialScroll else { return }
+                proxy.scrollTo(self.scrollerBottomID, anchor: .bottom)
+                self.hasPerformedInitialScroll = true
+            }
             .onChange(of: self.viewModel.messages.count) { _, _ in
+                guard self.hasPerformedInitialScroll else { return }
                 withAnimation(.snappy(duration: 0.22)) {
                     proxy.scrollTo(self.scrollerBottomID, anchor: .bottom)
                 }
             }
             .onChange(of: self.viewModel.pendingRunCount) { _, _ in
+                guard self.hasPerformedInitialScroll else { return }
                 withAnimation(.snappy(duration: 0.22)) {
                     proxy.scrollTo(self.scrollerBottomID, anchor: .bottom)
                 }