adds the ability to rename chats

ios/Packages/Sybil/Sources/Sybil/SybilAPIClient.swift

@@ -74,6 +74,16 @@ actor SybilAPIClient: SybilAPIClienting {
         return response.chat
     }
 
+    func updateChatTitle(chatID: String, title: String) async throws -> ChatSummary {
+        let response = try await request(
+            "/v1/chats/\(chatID)",
+            method: "PATCH",
+            body: AnyEncodable(ChatTitleUpdateBody(title: title)),
+            responseType: ChatCreateResponse.self
+        )
+        return response.chat
+    }
+
     func deleteChat(chatID: String) async throws {
         _ = try await request("/v1/chats/\(chatID)", method: "DELETE", responseType: DeleteResponse.self)
     }
@@ -640,6 +650,10 @@ private struct ChatCreateBody: Encodable {
     var messages: [CompletionRequestMessage]?
 }
 
+private struct ChatTitleUpdateBody: Encodable {
+    var title: String
+}
+
 private struct SearchCreateBody: Encodable {
     var title: String?
     var query: String?