Activate a project in this client ProjectManager.
Waits until ProjectManager.rpc_activate_project replies, then updates is_active / active_project. The daemon replies before its filesystem scan, so this returns quickly and the scan keeps running there. Callers that send another RPC must yield this method first: the client allows one request in flight, and a call queued while this one is still running waits for it.
The RPC does not persist UI selection (Config2 Settings.Window owns that).
| project |
The project folder to activate (must have is_project = true) |
| pending |
When false, do not send Folder.fetch_pending_approvals |