Now that https://github.com/openai/codex/pull/1373 simplified the sandbox config, we can print something much simpler in the TUI (and in `codex exec`) to summarize the sandbox config. Before:  With this change:  For reference, my `config.toml` contains: ``` [sandbox] mode = "workspace-write" writable_roots = ["/tmp", "/Users/mbolin/.pyenv/shims"] ``` Fixes https://github.com/openai/codex/issues/1248