TUI: Show apply patch diff. Stack: [2/2] (#2050)

Show the diff for apply patch

<img width="801" height="345" alt="image"
src="https://github.com/user-attachments/assets/a15d6112-e83e-4612-a2bd-43285689a358"
/>


Stack:
-> #2050
#2049

codex-rs/tui/src/lib.rs

@@ -30,6 +30,7 @@ mod chatwidget;
 mod citation_regex;
 mod cli;
 mod colors;
+mod common;
 pub mod custom_terminal;
 mod diff_render;
 mod exec_command;