Remove the legacy TUI split (#15922)

This is the part 1 of 2 PRs that will delete the `tui` /
`tui_app_server` split. This part simply deletes the existing `tui`
directory and marks the `tui_app_server` feature flag as removed. I left
the `tui_app_server` feature flag in place for now so its presence
doesn't result in an error. It is simply ignored.

Part 2 will rename the `tui_app_server` directory `tui`. I did this as
two parts to reduce visible code churn.

codex-rs/cli/src/main.rs

@@ -24,10 +24,10 @@ use codex_execpolicy::ExecPolicyCheckCommand;
 use codex_responses_api_proxy::Args as ResponsesApiProxyArgs;
 use codex_state::StateRuntime;
 use codex_state::state_db_path;
-use codex_tui::AppExitInfo;
-use codex_tui::Cli as TuiCli;
-use codex_tui::ExitReason;
-use codex_tui::update_action::UpdateAction;
+use codex_tui_app_server::AppExitInfo;
+use codex_tui_app_server::Cli as TuiCli;
+use codex_tui_app_server::ExitReason;
+use codex_tui_app_server::update_action::UpdateAction;
 use codex_utils_cli::CliConfigOverrides;
 use owo_colors::OwoColorize;
 use std::io::IsTerminal;
@@ -525,7 +525,7 @@ struct FeatureToggles {
 
 #[derive(Debug, Default, Parser, Clone)]
 struct InteractiveRemoteOptions {
-    /// Connect the app-server-backed TUI to a remote app server websocket endpoint.
+    /// Connect the TUI to a remote app server websocket endpoint.
     ///
     /// Accepted forms: `ws://host:port` or `wss://host:port`.
     #[arg(long = "remote", value_name = "ADDR")]
@@ -1226,7 +1226,6 @@ async fn run_interactive_tui(
         }
     }
 
-    let use_app_server_tui = codex_tui::should_use_app_server_tui(&interactive).await?;
     let normalized_remote = remote
         .as_deref()
         .map(codex_tui_app_server::normalize_remote_addr)
@@ -1237,93 +1236,19 @@ async fn run_interactive_tui(
             "`--remote-auth-token-env` requires `--remote`.",
         ));
     }
-    if normalized_remote.is_some() && !use_app_server_tui {
-        return Ok(AppExitInfo::fatal(
-            "`--remote` requires the `tui_app_server` feature flag to be enabled.",
-        ));
-    }
-    if use_app_server_tui {
-        let remote_auth_token = remote_auth_token_env
-            .as_deref()
-            .map(read_remote_auth_token_from_env_var)
-            .transpose()
-            .map_err(std::io::Error::other)?;
-        codex_tui_app_server::run_main(
-            into_app_server_tui_cli(interactive),
-            arg0_paths,
-            codex_core::config_loader::LoaderOverrides::default(),
-            normalized_remote,
-            remote_auth_token,
-        )
-        .await
-        .map(into_legacy_app_exit_info)
-    } else {
-        codex_tui::run_main(
-            interactive,
-            arg0_paths,
-            codex_core::config_loader::LoaderOverrides::default(),
-        )
-        .await
-    }
-}
-
-fn into_app_server_tui_cli(cli: TuiCli) -> codex_tui_app_server::Cli {
-    codex_tui_app_server::Cli {
-        prompt: cli.prompt,
-        images: cli.images,
-        resume_picker: cli.resume_picker,
-        resume_last: cli.resume_last,
-        resume_session_id: cli.resume_session_id,
-        resume_show_all: cli.resume_show_all,
-        fork_picker: cli.fork_picker,
-        fork_last: cli.fork_last,
-        fork_session_id: cli.fork_session_id,
-        fork_show_all: cli.fork_show_all,
-        model: cli.model,
-        oss: cli.oss,
-        oss_provider: cli.oss_provider,
-        config_profile: cli.config_profile,
-        sandbox_mode: cli.sandbox_mode,
-        approval_policy: cli.approval_policy,
-        full_auto: cli.full_auto,
-        dangerously_bypass_approvals_and_sandbox: cli.dangerously_bypass_approvals_and_sandbox,
-        cwd: cli.cwd,
-        web_search: cli.web_search,
-        add_dir: cli.add_dir,
-        no_alt_screen: cli.no_alt_screen,
-        config_overrides: cli.config_overrides,
-    }
-}
-
-fn into_legacy_update_action(
-    action: codex_tui_app_server::update_action::UpdateAction,
-) -> UpdateAction {
-    match action {
-        codex_tui_app_server::update_action::UpdateAction::NpmGlobalLatest => {
-            UpdateAction::NpmGlobalLatest
-        }
-        codex_tui_app_server::update_action::UpdateAction::BunGlobalLatest => {
-            UpdateAction::BunGlobalLatest
-        }
-        codex_tui_app_server::update_action::UpdateAction::BrewUpgrade => UpdateAction::BrewUpgrade,
-    }
-}
-
-fn into_legacy_exit_reason(reason: codex_tui_app_server::ExitReason) -> ExitReason {
-    match reason {
-        codex_tui_app_server::ExitReason::UserRequested => ExitReason::UserRequested,
-        codex_tui_app_server::ExitReason::Fatal(message) => ExitReason::Fatal(message),
-    }
-}
-
-fn into_legacy_app_exit_info(exit_info: codex_tui_app_server::AppExitInfo) -> AppExitInfo {
-    AppExitInfo {
-        token_usage: exit_info.token_usage,
-        thread_id: exit_info.thread_id,
-        thread_name: exit_info.thread_name,
-        update_action: exit_info.update_action.map(into_legacy_update_action),
-        exit_reason: into_legacy_exit_reason(exit_info.exit_reason),
-    }
+    let remote_auth_token = remote_auth_token_env
+        .as_deref()
+        .map(read_remote_auth_token_from_env_var)
+        .transpose()
+        .map_err(std::io::Error::other)?;
+    codex_tui_app_server::run_main(
+        interactive,
+        arg0_paths,
+        codex_core::config_loader::LoaderOverrides::default(),
+        normalized_remote,
+        remote_auth_token,
+    )
+    .await
 }
 
 fn confirm(prompt: &str) -> std::io::Result<bool> {