ACP champagne (#35609)

cherry pick changes from #35510 onto latest main

Release Notes:

- N/A

---------

Co-authored-by: Nathan Sobo <nathan@zed.dev>
Co-authored-by: Antonio Scandurra <me@as-cii.com>
Co-authored-by: Lukas Wirth <lukas@zed.dev>

crates/agent_servers/src/acp/v1.rs

@@ -169,11 +169,15 @@ impl AgentConnection for AcpConnection {
         })
     }
 
-    fn prompt(&self, params: acp::PromptRequest, cx: &mut App) -> Task<Result<()>> {
+    fn prompt(
+        &self,
+        params: acp::PromptRequest,
+        cx: &mut App,
+    ) -> Task<Result<acp::PromptResponse>> {
         let conn = self.connection.clone();
         cx.foreground_executor().spawn(async move {
-            conn.prompt(params).await?;
-            Ok(())
+            let response = conn.prompt(params).await?;
+            Ok(response)
         })
     }