Report typing status

Pass YES when typing starts. Pass NO after sending, losing focus, switching conversations, or stopping input:

[[OIMManager manager] changeInputStates:conversationID
                                  focus:YES
                              onSuccess:nil
                              onFailure:nil];

Typing status is scoped to conversationID; it does not save a draft or add an item to the message list. Throttle the start-typing call and deduplicate repeated state. A successful callback means only that the server accepted the request, not that the remote UI has updated.

Merge typing changes from OIMConversationListener.onConversationUserInputStatusChanged:. Replace the platformIDs snapshot by conversationID:userID. For complete listener registration and cleanup, see Retrieve the conversation list.