Move disable_paste_burst under [tui] (#41976)

## What changed

- Add `tui.disable_paste_burst` as the preferred configuration key.
- Keep the top-level `disable_paste_burst` key as a legacy fallback.
- Give the `[tui]` setting precedence when both keys are present, while preserving configuration-layer precedence.

## Testing

Add configuration tests covering defaults, both key locations, precedence between the keys, and command-line overrides.

GitOrigin-RevId: e7fc9337d5b19d2fd9407e08b8301cee77a11779

codex-rs/config/src/config_toml.rs

@@ -487,9 +487,7 @@ pub struct ConfigToml {
     /// Defaults to `true`.
     pub check_for_update_on_startup: Option<bool>,
 
-    /// When true, disables burst-paste detection for typed input entirely.
+    /// Legacy fallback for `tui.disable_paste_burst`. Prefer the setting under `[tui]`.
-    /// All characters are inserted as they are received, and no buffering
-    /// or placeholder replacement will occur for fast keypress bursts.
     pub disable_paste_burst: Option<bool>,
 
     /// When `false`, disables analytics across Codex product surfaces in this machine.

codex-rs/config/src/types.rs

@@ -710,6 +710,12 @@ pub struct Tui {
     #[serde(default = "default_true")]
     pub show_tooltips: bool,
 
+    /// When true, disables burst-paste detection for typed input entirely.
+    /// All characters are inserted as they are received, and no buffering
+    /// or placeholder replacement will occur for fast keypress bursts.
+    /// Overrides the legacy top-level `disable_paste_burst` setting. Defaults to `false`.
+    pub disable_paste_burst: Option<bool>,
+
     /// Start the composer in Vim mode (`Normal`) by default.
     /// Defaults to `false`.
     #[serde(default)]

codex-rs/core/config.schema.json

@@ -3772,6 +3772,10 @@
           "description": "Enable animations (welcome screen, shimmer effects, spinners). Defaults to `true`.",
           "type": "boolean"
         },
+        "disable_paste_burst": {
+          "description": "When true, disables burst-paste detection for typed input entirely. All characters are inserted as they are received, and no buffering or placeholder replacement will occur for fast keypress bursts. Overrides the legacy top-level `disable_paste_burst` setting. Defaults to `false`.",
+          "type": "boolean"
+        },
         "keymap": {
           "allOf": [
             {
@@ -5798,7 +5802,7 @@
       "type": "string"
     },
     "disable_paste_burst": {
-      "description": "When true, disables burst-paste detection for typed input entirely. All characters are inserted as they are received, and no buffering or placeholder replacement will occur for fast keypress bursts.",
+      "description": "Legacy fallback for `tui.disable_paste_burst`. Prefer the setting under `[tui]`.",
       "type": "boolean"
     },
     "experimental_compact_prompt_file": {

codex-rs/core/src/config/config_tests.rs

@@ -1210,6 +1210,7 @@ fn config_toml_deserializes_model_availability_nux() {
             notification_settings: TuiNotificationSettings::default(),
             animations: true,
             show_tooltips: true,
+            disable_paste_burst: None,
             vim_mode_default: false,
             raw_output_mode: false,
             alternate_screen: AltScreenMode::default(),
@@ -4289,6 +4290,7 @@ fn tui_config_missing_notifications_field_defaults_to_enabled() {
             notification_settings: TuiNotificationSettings::default(),
             animations: true,
             show_tooltips: true,
+            disable_paste_burst: None,
             vim_mode_default: false,
             raw_output_mode: false,
             alternate_screen: AltScreenMode::Auto,
@@ -4307,6 +4309,85 @@ fn tui_config_missing_notifications_field_defaults_to_enabled() {
     );
 }
 
+#[tokio::test]
+async fn runtime_config_resolves_disable_paste_burst() -> anyhow::Result<()> {
+    for (toml, expected) in [
+        ("", false),
+        ("disable_paste_burst = true", true),
+        ("disable_paste_burst = true\n[tui]", true),
+        ("[tui]\ndisable_paste_burst = true", true),
+        (
+            "disable_paste_burst = true\n[tui]\ndisable_paste_burst = false",
+            false,
+        ),
+        (
+            "disable_paste_burst = false\n[tui]\ndisable_paste_burst = true",
+            true,
+        ),
+    ] {
+        let config = Config::load_from_base_config_with_overrides(
+            toml::from_str(toml)?,
+            ConfigOverrides::default(),
+            tempdir()?.abs(),
+        )
+        .await?;
+
+        assert_eq!(config.disable_paste_burst, expected, "config: {toml}");
+    }
+    Ok(())
+}
+
+#[tokio::test]
+async fn disable_paste_burst_preserves_layering_and_new_key_precedence() -> anyhow::Result<()> {
+    for (toml, key, value, expected) in [
+        (
+            "disable_paste_burst = true",
+            "disable_paste_burst",
+            false,
+            false,
+        ),
+        (
+            "disable_paste_burst = true",
+            "tui.disable_paste_burst",
+            false,
+            false,
+        ),
+        (
+            "[tui]\ndisable_paste_burst = true",
+            "tui.disable_paste_burst",
+            false,
+            false,
+        ),
+        (
+            "[tui]\ndisable_paste_burst = true",
+            "disable_paste_burst",
+            false,
+            true,
+        ),
+        (
+            "[tui]\ndisable_paste_burst = false",
+            "disable_paste_burst",
+            true,
+            false,
+        ),
+    ] {
+        let codex_home = TempDir::new()?;
+        std::fs::write(codex_home.path().join(CONFIG_TOML_FILE), toml)?;
+        let config = ConfigBuilder::without_managed_config_for_tests()
+            .codex_home(codex_home.path().to_path_buf())
+            .fallback_cwd(Some(codex_home.path().to_path_buf()))
+            .cli_overrides(vec![(key.to_string(), TomlValue::Boolean(value))])
+            .build()
+            .await?;
+
+        assert_eq!(
+            config.disable_paste_burst, expected,
+            "config: {toml}, override: {key}={value}"
+        );
+    }
+    Ok(())
+}
+
 #[tokio::test]
 async fn runtime_config_resolves_terminal_resize_reflow_defaults_and_overrides() {
     let cfg = Config::load_from_base_config_with_overrides(

codex-rs/core/src/config/mod.rs

@@ -4302,7 +4302,12 @@ impl Config {
             active_project,
             notices,
             check_for_update_on_startup,
-            disable_paste_burst: cfg.disable_paste_burst.unwrap_or(false),
+            disable_paste_burst: cfg
+                .tui
+                .as_ref()
+                .and_then(|tui| tui.disable_paste_burst)
+                .or(cfg.disable_paste_burst)
+                .unwrap_or(false),
             analytics_enabled: cfg.analytics.as_ref().and_then(|a| a.enabled),
             feedback_enabled: cfg
                 .feedback