Allow clients to run Zed tasks on remote projects (#12199)

Release Notes:

- Enabled Zed tasks on remote projects with ssh connection string
specified

---------

Co-authored-by: Conrad Irwin <conrad@zed.dev>

crates/collab/src/db/queries/projects.rs

@@ -1101,6 +1101,36 @@ impl Database {
         .map(|guard| guard.into_inner())
     }
 
+    /// Returns the host connection for a request to join a shared project.
+    pub async fn host_for_owner_project_request(
+        &self,
+        project_id: ProjectId,
+        _connection_id: ConnectionId,
+        user_id: UserId,
+    ) -> Result<ConnectionId> {
+        self.project_transaction(project_id, |tx| async move {
+            let (project, dev_server_project) = project::Entity::find_by_id(project_id)
+                .find_also_related(dev_server_project::Entity)
+                .one(&*tx)
+                .await?
+                .ok_or_else(|| anyhow!("no such project"))?;
+
+            let Some(dev_server_project) = dev_server_project else {
+                return Err(anyhow!("not a dev server project"))?;
+            };
+            let dev_server = dev_server::Entity::find_by_id(dev_server_project.dev_server_id)
+                .one(&*tx)
+                .await?
+                .ok_or_else(|| anyhow!("no such dev server"))?;
+            if dev_server.user_id != user_id {
+                return Err(anyhow!("not your project"))?;
+            }
+            project.host_connection()
+        })
+        .await
+        .map(|guard| guard.into_inner())
+    }
+
     pub async fn connections_for_buffer_update(
         &self,
         project_id: ProjectId,

crates/collab/src/rpc.rs

@@ -446,6 +446,12 @@ impl Server {
             .add_message_handler(update_language_server)
             .add_message_handler(update_diagnostic_summary)
             .add_message_handler(update_worktree_settings)
+            .add_request_handler(user_handler(
+                forward_project_request_for_owner::<proto::TaskContextForLocation>,
+            ))
+            .add_request_handler(user_handler(
+                forward_project_request_for_owner::<proto::TaskTemplates>,
+            ))
             .add_request_handler(user_handler(
                 forward_read_only_project_request::<proto::GetHover>,
             ))
@@ -2889,6 +2895,31 @@ where
     Ok(())
 }
 
+/// forward a project request to the dev server. Only allowed
+/// if it's your dev server.
+async fn forward_project_request_for_owner<T>(
+    request: T,
+    response: Response<T>,
+    session: UserSession,
+) -> Result<()>
+where
+    T: EntityMessage + RequestMessage,
+{
+    let project_id = ProjectId::from_proto(request.remote_entity_id());
+
+    let host_connection_id = session
+        .db()
+        .await
+        .host_for_owner_project_request(project_id, session.connection_id, session.user_id())
+        .await?;
+    let payload = session
+        .peer
+        .forward_request(session.connection_id, host_connection_id, request)
+        .await?;
+    response.send(payload)?;
+    Ok(())
+}
+
 /// forward a project request to the host. These requests are disallowed
 /// for guests.
 async fn forward_mutating_project_request<T>(