Rename OpenWorktree message to JoinWorktree

We'll repurpose the name 'OpenWorktree' for opening a local
worktree while signed in, and advertising the open status to
the worktree's collaborators.

zrpc/src/proto.rs

@@ -138,8 +138,8 @@ messages!(
     LeaveChannel,
     OpenBuffer,
     OpenBufferResponse,
-    OpenWorktree,
-    OpenWorktreeResponse,
+    JoinWorktree,
+    JoinWorktreeResponse,
     Ping,
     RemovePeer,
     SaveBuffer,
@@ -156,7 +156,7 @@ request_messages!(
     (GetUsers, GetUsersResponse),
     (JoinChannel, JoinChannelResponse),
     (OpenBuffer, OpenBufferResponse),
-    (OpenWorktree, OpenWorktreeResponse),
+    (JoinWorktree, JoinWorktreeResponse),
     (Ping, Ack),
     (SaveBuffer, BufferSaved),
     (UpdateBuffer, Ack),
@@ -172,7 +172,7 @@ entity_messages!(
     CloseBuffer,
     CloseWorktree,
     OpenBuffer,
-    OpenWorktree,
+    JoinWorktree,
     RemovePeer,
     SaveBuffer,
     UpdateBuffer,