Fix iOS chat scroll pinning

ios/Packages/Sybil/Sources/Sybil/SybilChatTranscriptView.swift

@@ -7,38 +7,55 @@ struct SybilChatTranscriptView: View {
     var isSending: Bool
     var topContentInset: CGFloat = 0
     var bottomContentInset: CGFloat = 0
+    var bottomPinRequestID: Int = 0
 
-    private var hasPendingAssistant: Bool {
-        messages.contains { message in
-            message.id.hasPrefix("temp-assistant-") && message.content.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty
+    private let bottomAnchorID = "sybil-chat-transcript-bottom-anchor"
+
+    var body: some View {
+        ScrollViewReader { proxy in
+            ScrollView {
+                LazyVStack(alignment: .leading, spacing: 26) {
+                    if isLoading && messages.isEmpty {
+                        Text("Loading messages…")
+                            .font(.sybil(.footnote))
+                            .foregroundStyle(SybilTheme.textMuted)
+                            .padding(.top, 24)
+                    }
+
+                    ForEach(messages) { message in
+                        MessageBubble(message: message, isSending: isSending)
+                            .frame(maxWidth: .infinity)
+                    }
+
+                    Color.clear
+                        .frame(height: 18 + bottomContentInset)
+                        .id(bottomAnchorID)
+                }
+                .frame(maxWidth: .infinity, alignment: .leading)
+                .padding(.horizontal, 14)
+                .padding(.top, 18 + topContentInset)
+            }
+            .frame(maxWidth: .infinity, alignment: .leading)
+            .scrollDismissesKeyboard(.interactively)
+            .onAppear {
+                scrollToBottom(with: proxy, animated: false)
+            }
+            .onChange(of: bottomPinRequestID) { _, _ in
+                scrollToBottom(with: proxy, animated: true)
+            }
         }
     }
 
-    var body: some View {
-        ScrollView {
-            LazyVStack(alignment: .leading, spacing: 26) {
-                ForEach(messages.reversed()) { message in
-                    MessageBubble(message: message, isSending: isSending)
-                        .frame(maxWidth: .infinity)
-                        .scaleEffect(x: 1, y: -1)
-                }
-
-                if isLoading && messages.isEmpty {
-                    Text("Loading messages…")
-                        .font(.sybil(.footnote))
-                        .foregroundStyle(SybilTheme.textMuted)
-                        .padding(.top, 24)
-                        .scaleEffect(x: 1, y: -1)
-                }
-            }
-            .frame(maxWidth: .infinity, alignment: .leading)
-            .padding(.horizontal, 14)
-            .padding(.top, 18 + bottomContentInset)
-            .padding(.bottom, 18 + topContentInset)
+    private func scrollToBottom(with proxy: ScrollViewProxy, animated: Bool) {
+        let action = {
+            proxy.scrollTo(bottomAnchorID, anchor: .bottom)
+        }
+
+        if animated {
+            withAnimation(.easeOut(duration: 0.18), action)
+        } else {
+            action()
         }
-        .frame(maxWidth: .infinity, alignment: .leading)
-        .scrollDismissesKeyboard(.interactively)
-        .scaleEffect(x: 1, y: -1)
     }
 }
 

ios/Packages/Sybil/Sources/Sybil/SybilViewModel.swift

@@ -107,6 +107,7 @@ final class SybilViewModel {
     var isLoadingCollections = false
     var isLoadingSelection = false
     var isCreatingSearchChat = false
+    var chatBottomPinRequestID = 0
     var errorMessage: String?
 
     var composer = ""
@@ -1699,6 +1700,10 @@ final class SybilViewModel {
         isLoadingSelection = false
     }
 
+    private func requestChatBottomPin() {
+        chatBottomPinRequestID += 1
+    }
+
     private func startSelectionRefreshTask() -> Task<Void, Never> {
         isLoadingSelection = true
         let task = Task { [weak self] in
@@ -1752,6 +1757,7 @@ final class SybilViewModel {
                     }
                     selectedChat = chat
                     selectedSearch = nil
+                    requestChatBottomPin()
 
                     if let provider = chat.lastUsedProvider,
                        let model = chat.lastUsedModel,
@@ -1824,6 +1830,7 @@ final class SybilViewModel {
         } else {
             pendingDraftChatState = PendingChatState(chatID: nil, messages: optimisticMessages)
         }
+        requestChatBottomPin()
 
         if chatID == nil {
             let created = try await client.createChat(title: nil)
@@ -1871,6 +1878,7 @@ final class SybilViewModel {
         if let draftPending = pendingDraftChatState {
             pendingDraftChatState = nil
             pendingChatStates[chatID] = PendingChatState(chatID: chatID, messages: draftPending.messages)
+            requestChatBottomPin()
         } else if pendingChatStates[chatID] == nil {
             pendingChatStates[chatID] = PendingChatState(chatID: chatID, messages: optimisticMessages)
         } else {

ios/Packages/Sybil/Sources/Sybil/SybilWorkspaceView.swift

@@ -194,7 +194,8 @@ struct SybilWorkspaceView: View {
                         isLoading: viewModel.isLoadingSelection,
                         isSending: viewModel.isSendingVisibleChat,
                         topContentInset: showsCustomWorkspaceNavigation ? customWorkspaceNavigationContentInset : 0,
-                        bottomContentInset: viewModel.showsComposer ? composerOverlayContentInset : 0
+                        bottomContentInset: viewModel.showsComposer ? composerOverlayContentInset : 0,
+                        bottomPinRequestID: viewModel.chatBottomPinRequestID
                     )
                     .id(transcriptScrollContextID)
                 }