Move terminal module to terminal-detection crate (#15216)

- Move core/src/terminal.rs and its tests into a standalone
terminal-detection workspace crate.
- Update direct consumers to depend on codex-terminal-detection and
import terminal APIs directly.

---------

Co-authored-by: Codex <noreply@openai.com>

codex-rs/tui_app_server/src/app.rs

@@ -96,6 +96,7 @@ use codex_protocol::protocol::SandboxPolicy;
 use codex_protocol::protocol::SessionSource;
 use codex_protocol::protocol::SkillErrorInfo;
 use codex_protocol::protocol::TokenUsage;
+use codex_terminal_detection::user_agent;
 use codex_utils_absolute_path::AbsolutePathBuf;
 use color_eyre::eyre::Result;
 use color_eyre::eyre::WrapErr;
@@ -2965,7 +2966,7 @@ impl App {
             auth_mode,
             codex_core::default_client::originator().value,
             config.otel.log_user_prompt,
-            codex_core::terminal::user_agent(),
+            user_agent(),
             SessionSource::Cli,
         );
         if config

codex-rs/tui_app_server/src/chatwidget.rs

@@ -94,8 +94,6 @@ use codex_core::git_info::local_git_branches;
 use codex_core::plugins::PluginsManager;
 use codex_core::project_doc::DEFAULT_PROJECT_DOC_FILENAME;
 use codex_core::skills::model::SkillMetadata;
-use codex_core::terminal::TerminalName;
-use codex_core::terminal::terminal_info;
 #[cfg(target_os = "windows")]
 use codex_core::windows_sandbox::WindowsSandboxLevelExt;
 use codex_otel::RuntimeMetricsSummary;
@@ -199,6 +197,8 @@ use codex_protocol::request_user_input::RequestUserInputEvent;
 use codex_protocol::request_user_input::RequestUserInputQuestionOption;
 use codex_protocol::user_input::TextElement;
 use codex_protocol::user_input::UserInput;
+use codex_terminal_detection::TerminalName;
+use codex_terminal_detection::terminal_info;
 use codex_utils_sleep_inhibitor::SleepInhibitor;
 use crossterm::event::KeyCode;
 use crossterm::event::KeyEvent;

codex-rs/tui_app_server/src/chatwidget/tests.rs

@@ -61,7 +61,6 @@ use codex_core::features::FEATURES;
 use codex_core::features::Feature;
 use codex_core::models_manager::collaboration_mode_presets::CollaborationModesConfig;
 use codex_core::skills::model::SkillMetadata;
-use codex_core::terminal::TerminalName;
 use codex_otel::RuntimeMetricsSummary;
 use codex_otel::SessionTelemetry;
 use codex_protocol::ThreadId;
@@ -144,6 +143,7 @@ use codex_protocol::request_user_input::RequestUserInputQuestion;
 use codex_protocol::request_user_input::RequestUserInputQuestionOption;
 use codex_protocol::user_input::TextElement;
 use codex_protocol::user_input::UserInput;
+use codex_terminal_detection::TerminalName;
 use codex_utils_absolute_path::AbsolutePathBuf;
 use codex_utils_approval_presets::builtin_approval_presets;
 use crossterm::event::KeyCode;

codex-rs/tui_app_server/src/diff_render.rs

@@ -93,9 +93,9 @@ use crate::terminal_palette::indexed_color;
 use crate::terminal_palette::rgb_color;
 use crate::terminal_palette::stdout_color_level;
 use codex_core::git_info::get_git_repo_root;
-use codex_core::terminal::TerminalName;
-use codex_core::terminal::terminal_info;
 use codex_protocol::protocol::FileChange;
+use codex_terminal_detection::TerminalName;
+use codex_terminal_detection::terminal_info;
 
 /// Classifies a diff line for gutter sign rendering and style selection.
 ///

codex-rs/tui_app_server/src/lib.rs

@@ -38,7 +38,6 @@ use codex_core::format_exec_policy_error_with_source;
 use codex_core::path_utils;
 use codex_core::read_session_meta_line;
 use codex_core::state_db::get_state_db;
-use codex_core::terminal::Multiplexer;
 use codex_core::windows_sandbox::WindowsSandboxLevelExt;
 use codex_protocol::ThreadId;
 use codex_protocol::config_types::AltScreenMode;
@@ -49,6 +48,8 @@ use codex_protocol::protocol::RolloutItem;
 use codex_protocol::protocol::RolloutLine;
 use codex_protocol::protocol::TurnContextItem;
 use codex_state::log_db;
+use codex_terminal_detection::Multiplexer;
+use codex_terminal_detection::terminal_info;
 use codex_utils_absolute_path::AbsolutePathBuf;
 use codex_utils_oss::ensure_oss_provider_ready;
 use codex_utils_oss::get_default_model_for_oss_provider;
@@ -1485,7 +1486,7 @@ fn determine_alt_screen_mode(no_alt_screen: bool, tui_alternate_screen: AltScree
             AltScreenMode::Always => true,
             AltScreenMode::Never => false,
             AltScreenMode::Auto => {
-                let terminal_info = codex_core::terminal::terminal_info();
+                let terminal_info = terminal_info();
                 !matches!(terminal_info.multiplexer, Some(Multiplexer::Zellij { .. }))
             }
         }