feat: Set chat name (#4974)

Set chat name with `/name` so they appear in the codex resume page:


https://github.com/user-attachments/assets/c0252bba-3a53-44c7-a740-f4690a3ad405

codex-rs/tui/src/bottom_pane/mod.rs

@@ -25,7 +25,7 @@ pub mod custom_prompt_view;
 mod file_search_popup;
 mod footer;
 mod list_selection_view;
-mod prompt_args;
+pub mod prompt_args;
 pub(crate) use list_selection_view::SelectionViewParams;
 mod paste_burst;
 pub mod popup_consts;