In local projects, initialize the list of agents in the agent server store immediately. Previously we were initializing the list only after a delay, in an attempt to avoid sending the `ExternalAgentsUpdated` message to the downstream client (if any) before its handlers were initialized. But we already have a separate codepath for that situation, in the `AgentServerStore::shared`, and we can insert the delay in that place instead. Release Notes: - acp: Fixed a bug where starting an external agent thread soon after Zed starts up would show a "not registered" error. --------- Co-authored-by: Michael <michael@zed.dev> Co-authored-by: Agus <agus@zed.dev>