hosted projects (#8627)

- **Allow joining a hosted project**

You can't yet do anything in a hosted project, but you can join it and
look how empty it is.

Release Notes:

- N/A

crates/rpc/proto/zed.proto

@@ -196,6 +196,8 @@ message Envelope {
 
         GetImplementation get_implementation = 162;
         GetImplementationResponse get_implementation_response = 163;
+
+        JoinHostedProject join_hosted_project = 164;
     }
 
     reserved 158 to 161;
@@ -230,6 +232,7 @@ enum ErrorCode {
     CircularNesting = 10;
     WrongMoveTarget = 11;
     UnsharedItem = 12;
+    NoSuchProject = 13;
     reserved 6;
 }
 
@@ -404,11 +407,17 @@ message JoinProject {
     uint64 project_id = 1;
 }
 
+message JoinHostedProject {
+    uint64 id = 1;
+}
+
 message JoinProjectResponse {
+    uint64 project_id = 5;
     uint32 replica_id = 1;
     repeated WorktreeMetadata worktrees = 2;
     repeated Collaborator collaborators = 3;
     repeated LanguageServer language_servers = 4;
+    ChannelRole role = 6;
 }
 
 message LeaveProject {

crates/rpc/src/proto.rs

@@ -206,6 +206,7 @@ messages!(
     (JoinChannelChat, Foreground),
     (JoinChannelChatResponse, Foreground),
     (JoinProject, Foreground),
+    (JoinHostedProject, Foreground),
     (JoinProjectResponse, Foreground),
     (JoinRoom, Foreground),
     (JoinRoomResponse, Foreground),
@@ -329,6 +330,7 @@ request_messages!(
     (JoinChannel, JoinRoomResponse),
     (JoinChannelBuffer, JoinChannelBufferResponse),
     (JoinChannelChat, JoinChannelChatResponse),
+    (JoinHostedProject, JoinProjectResponse),
     (JoinProject, JoinProjectResponse),
     (JoinRoom, JoinRoomResponse),
     (LeaveChannelBuffer, Ack),