Add logout command to CLI and TUI (#1932)

## Summary
- support `codex logout` via new subcommand and helper that removes the
stored `auth.json`
- expose a `logout` function in `codex-login` and test it
- add `/logout` slash command in the TUI; command list is filtered when
not logged in and the handler deletes `auth.json` then exits

## Testing
- `just fix` *(fails: failed to get `diffy` from crates.io)*
- `cargo test --all-features` *(fails: failed to get `diffy` from
crates.io)*

------
https://chatgpt.com/codex/tasks/task_i_68945c3facac832ca83d48499716fb51

codex-rs/cli/src/login.rs

@@ -8,6 +8,7 @@ use codex_login::OPENAI_API_KEY_ENV_VAR;
 use codex_login::load_auth;
 use codex_login::login_with_api_key;
 use codex_login::login_with_chatgpt;
+use codex_login::logout;
 
 pub async fn run_login_with_chatgpt(cli_config_overrides: CliConfigOverrides) -> ! {
     let config = load_config_or_exit(cli_config_overrides);
@@ -80,6 +81,25 @@ pub async fn run_login_status(cli_config_overrides: CliConfigOverrides) -> ! {
     }
 }
 
+pub async fn run_logout(cli_config_overrides: CliConfigOverrides) -> ! {
+    let config = load_config_or_exit(cli_config_overrides);
+
+    match logout(&config.codex_home) {
+        Ok(true) => {
+            eprintln!("Successfully logged out");
+            std::process::exit(0);
+        }
+        Ok(false) => {
+            eprintln!("Not logged in");
+            std::process::exit(0);
+        }
+        Err(e) => {
+            eprintln!("Error logging out: {e}");
+            std::process::exit(1);
+        }
+    }
+}
+
 fn load_config_or_exit(cli_config_overrides: CliConfigOverrides) -> Config {
     let cli_overrides = match cli_config_overrides.parse_overrides() {
         Ok(v) => v,

codex-rs/cli/src/main.rs

@@ -10,6 +10,7 @@ use codex_cli::SeatbeltCommand;
 use codex_cli::login::run_login_status;
 use codex_cli::login::run_login_with_api_key;
 use codex_cli::login::run_login_with_chatgpt;
+use codex_cli::login::run_logout;
 use codex_cli::proto;
 use codex_common::CliConfigOverrides;
 use codex_exec::Cli as ExecCli;
@@ -48,6 +49,9 @@ enum Subcommand {
     /// Manage login.
     Login(LoginCommand),
 
+    /// Remove stored authentication credentials.
+    Logout(LogoutCommand),
+
     /// Experimental: run Codex as an MCP server.
     Mcp,
 
@@ -106,6 +110,12 @@ enum LoginSubcommand {
     Status,
 }
 
+#[derive(Debug, Parser)]
+struct LogoutCommand {
+    #[clap(skip)]
+    config_overrides: CliConfigOverrides,
+}
+
 fn main() -> anyhow::Result<()> {
     arg0_dispatch_or_else(|codex_linux_sandbox_exe| async move {
         cli_main(codex_linux_sandbox_exe).await?;
@@ -147,6 +157,10 @@ async fn cli_main(codex_linux_sandbox_exe: Option<PathBuf>) -> anyhow::Result<()
                 }
             }
         }
+        Some(Subcommand::Logout(mut logout_cli)) => {
+            prepend_config_flags(&mut logout_cli.config_overrides, cli.config_overrides);
+            run_logout(logout_cli.config_overrides).await;
+        }
         Some(Subcommand::Proto(mut proto_cli)) => {
             prepend_config_flags(&mut proto_cli.config_overrides, cli.config_overrides);
             proto::run_main(proto_cli).await?;