Get terminal tool working in evals (#29831)

Bypass our terminal subsystem and just run a shell in a pty.

- [x] make sure we use the same working directory
- [x] strip control chars from the pty output (?)
- [x] tests

Release Notes:

- N/A

crates/assistant_tools/Cargo.toml

@@ -37,6 +37,8 @@ language.workspace = true
 language_model.workspace = true
 linkme.workspace = true
 open.workspace = true
+paths.workspace = true
+portable-pty.workspace = true
 project.workspace = true
 regex.workspace = true
 rust-embed.workspace = true
@@ -75,6 +77,8 @@ reqwest_client.workspace = true
 settings = { workspace = true, features = ["test-support"] }
 task = { workspace = true, features = ["test-support"]}
 tempfile.workspace = true
+theme.workspace = true
 tree-sitter-rust.workspace = true
 workspace = { workspace = true, features = ["test-support"] }
 unindent.workspace = true
+zlog.workspace = true