ACP history mentions (#36551)

- **TEMP**
- **Update @-mentions to use new history**

Closes #ISSUE

Release Notes:

- N/A

crates/acp_thread/Cargo.toml

@@ -18,7 +18,6 @@ test-support = ["gpui/test-support", "project/test-support", "dep:parking_lot"]
 [dependencies]
 action_log.workspace = true
 agent-client-protocol.workspace = true
-agent.workspace = true
 anyhow.workspace = true
 buffer_diff.workspace = true
 collections.workspace = true