agent2: Port edit_file tool (#35844)

TODO:
- [x] Authorization
- [x] Restore tests

Release Notes:

- N/A

---------

Co-authored-by: Antonio Scandurra <me@as-cii.com>
Co-authored-by: Ben Brandt <benjamin.j.brandt@gmail.com>

crates/agent2/src/tests/mod.rs

@@ -1,5 +1,4 @@
 use super::*;
-use crate::templates::Templates;
 use acp_thread::AgentConnection;
 use agent_client_protocol::{self as acp};
 use anyhow::Result;
@@ -273,7 +272,7 @@ async fn test_tool_authorization(cx: &mut TestAppContext) {
                 tool_name: ToolRequiringPermission.name().into(),
                 is_error: false,
                 content: "Allowed".into(),
-                output: None
+                output: Some("Allowed".into())
             }),
             MessageContent::ToolResult(LanguageModelToolResult {
                 tool_use_id: tool_call_auth_2.tool_call.id.0.to_string().into(),