adds the ability to rename chats

ios/Packages/Sybil/Tests/SybilTests/SybilTests.swift

@@ -9,6 +9,7 @@ private struct MockClientCallSnapshot: Sendable {
     var listSearches = 0
     var createChat = 0
     var getChat = 0
+    var updateChatTitle = 0
     var getSearch = 0
     var getActiveRuns = 0
     var runCompletionStream = 0
@@ -32,6 +33,7 @@ private actor MockSybilClient: SybilAPIClienting {
     private let chatDetails: [String: ChatDetail]
     private let searchDetails: [String: SearchDetail]
     private let createChatResponse: ChatSummary?
+    private let updateChatTitleResponses: [String: ChatSummary]
     private let activeRunsResponse: ActiveRunsResponse
 
     private var snapshot = MockClientCallSnapshot()
@@ -57,6 +59,7 @@ private actor MockSybilClient: SybilAPIClienting {
         chatDetails: [String: ChatDetail] = [:],
         searchDetails: [String: SearchDetail] = [:],
         createChatResponse: ChatSummary? = nil,
+        updateChatTitleResponses: [String: ChatSummary] = [:],
         activeRunsResponse: ActiveRunsResponse = ActiveRunsResponse(),
         workspaceItemsResponse: [WorkspaceItem]? = nil
     ) {
@@ -66,6 +69,7 @@ private actor MockSybilClient: SybilAPIClienting {
         self.chatDetails = chatDetails
         self.searchDetails = searchDetails
         self.createChatResponse = createChatResponse
+        self.updateChatTitleResponses = updateChatTitleResponses
         self.activeRunsResponse = activeRunsResponse
     }
 
@@ -182,6 +186,14 @@ private actor MockSybilClient: SybilAPIClienting {
         return detail
     }
 
+    func updateChatTitle(chatID: String, title: String) async throws -> ChatSummary {
+        snapshot.updateChatTitle += 1
+        guard let summary = updateChatTitleResponses[chatID] else {
+            throw UnexpectedClientCall()
+        }
+        return summary
+    }
+
     func deleteChat(chatID: String) async throws {
         throw UnexpectedClientCall()
     }
@@ -461,6 +473,42 @@ private func makeSearchDetail(id: String, date: Date, answer: String) -> SearchD
     #expect(viewModel.selectedChat?.messages.first?.content == "refreshed transcript")
 }
 
+@MainActor
+@Test func renameChatUpdatesSidebarAndSelectedTranscriptTitle() async throws {
+    let date = Date(timeIntervalSince1970: 1_700_000_150)
+    let original = makeChatSummary(id: "chat-rename", date: date)
+    let renamed = ChatSummary(
+        id: "chat-rename",
+        title: "Renamed chat",
+        createdAt: date,
+        updatedAt: date.addingTimeInterval(60),
+        initiatedProvider: .openai,
+        initiatedModel: "gpt-4.1-mini",
+        lastUsedProvider: .openai,
+        lastUsedModel: "gpt-4.1-mini"
+    )
+    let detail = makeChatDetail(id: "chat-rename", date: date, body: "existing transcript")
+    let client = MockSybilClient(
+        chatsResponse: [original],
+        updateChatTitleResponses: ["chat-rename": renamed]
+    )
+    let viewModel = SybilViewModel(settings: testSettings(named: #function)) { _ in client }
+    viewModel.isAuthenticated = true
+    viewModel.isCheckingSession = false
+    viewModel.chats = [original]
+    viewModel.workspaceItems = [WorkspaceItem(chat: original)]
+    viewModel.selectedItem = .chat("chat-rename")
+    viewModel.selectedChat = detail
+
+    await viewModel.renameChat(chatID: "chat-rename", title: " Renamed chat ")
+
+    let snapshot = await client.currentSnapshot()
+    #expect(snapshot.updateChatTitle == 1)
+    #expect(viewModel.sidebarItems.first?.title == "Renamed chat")
+    #expect(viewModel.selectedChat?.title == "Renamed chat")
+    #expect(viewModel.errorMessage == nil)
+}
+
 @MainActor
 @Test func foregroundSearchRefreshReloadsSelectedSearch() async throws {
     let date = Date(timeIntervalSince1970: 1_700_000_200)