Add message branching

Updated the behaviour of commands:

- `lmcli edit`
  - by default create a new branch/message branch with the edited contents
  - add --in-place to avoid creating a branch
  - no longer delete messages after the edited message
  - only do the edit, don't fetch a new response
- `lmcli retry`
  - create a new branch rather than replacing old messages
  - add --offset to change where to retry from

pkg/cmd/reply.go

@@ -31,9 +31,9 @@ func ReplyCmd(ctx *lmcli.Context) *cobra.Command {
 			}
 
 			cmdutil.HandleConversationReply(ctx, conversation, true, model.Message{
-				ConversationID:  conversation.ID,
-				Role:            model.MessageRoleUser,
-				Content: reply,
+				ConversationID: conversation.ID,
+				Role:           model.MessageRoleUser,
+				Content:        reply,
 			})
 			return nil
 		},