Refactor to use new ACP crate (#35043)

This will prepare us for running the protocol over MCP

Release Notes:

- N/A

---------

Co-authored-by: Ben Brandt <benjamin.j.brandt@gmail.com>
Co-authored-by: Conrad Irwin <conrad.irwin@gmail.com>
Co-authored-by: Richard Feldman <oss@rtfeldman.com>

crates/agent_servers/src/agent_servers.rs

@@ -1,7 +1,6 @@
 mod claude;
 mod gemini;
 mod settings;
-mod stdio_agent_server;
 
 #[cfg(test)]
 mod e2e_tests;
@@ -9,9 +8,8 @@ mod e2e_tests;
 pub use claude::*;
 pub use gemini::*;
 pub use settings::*;
-pub use stdio_agent_server::*;
 
-use acp_thread::AcpThread;
+use acp_thread::AgentConnection;
 use anyhow::Result;
 use collections::HashMap;
 use gpui::{App, AsyncApp, Entity, SharedString, Task};
@@ -20,6 +18,7 @@ use schemars::JsonSchema;
 use serde::{Deserialize, Serialize};
 use std::{
     path::{Path, PathBuf},
+    rc::Rc,
     sync::Arc,
 };
 use util::ResultExt as _;
@@ -33,14 +32,14 @@ pub trait AgentServer: Send {
     fn name(&self) -> &'static str;
     fn empty_state_headline(&self) -> &'static str;
     fn empty_state_message(&self) -> &'static str;
-    fn supports_always_allow(&self) -> bool;
 
-    fn new_thread(
+    fn connect(
         &self,
+        // these will go away when old_acp is fully removed
         root_dir: &Path,
         project: &Entity<Project>,
         cx: &mut App,
-    ) -> Task<Result<Entity<AcpThread>>>;
+    ) -> Task<Result<Rc<dyn AgentConnection>>>;
 }
 
 impl std::fmt::Debug for AgentServerCommand {