fix: is_inside_git_repo should take the directory as a param (#809)

https://github.com/openai/codex/pull/800 made `cwd` a property of
`Config` and made it so the `cwd` is not necessarily
`std::env::current_dir()`. As such, `is_inside_git_repo()` should check
`Config.cwd` rather than `std::env::current_dir()`.

This PR updates `is_inside_git_repo()` to take `Config` instead of an
arbitrary `PathBuf` to force the check to operate on a `Config` where
`cwd` has been resolved to what the user specified.

codex-rs/tui/src/lib.rs

@@ -114,7 +114,7 @@ pub fn run_main(cli: Cli) -> std::io::Result<()> {
     // modal. The flag is shown when the current working directory is *not*
     // inside a Git repository **and** the user did *not* pass the
     // `--allow-no-git-exec` flag.
-    let show_git_warning = !cli.skip_git_repo_check && !is_inside_git_repo();
+    let show_git_warning = !cli.skip_git_repo_check && !is_inside_git_repo(&config);
 
     try_run_ratatui_app(cli, config, show_git_warning, log_rx);
     Ok(())