feat: show MCP tool calls in codex exec subcommand (#841)

This is analogous to the change for the TUI in
https://github.com/openai/codex/pull/836, but for `codex exec`.

To test, I ran:

```
cargo run --bin codex-exec -- 'what is the weather in wellesley ma tomorrow'
```

and saw:


![image](https://github.com/user-attachments/assets/5714e07f-88c7-4dd9-aa0d-be54c1670533)

codex-rs/Cargo.lock

@@ -531,7 +531,9 @@ dependencies = [
  "chrono",
  "clap",
  "codex-core",
+ "mcp-types",
  "owo-colors 4.2.0",
+ "serde_json",
  "shlex",
  "tokio",
  "tracing",