Add TUI notification condition config (#17175)

Problem: TUI desktop notifications are hard-gated on terminal focus, so
terminal/IDE hosts that want in-focus notifications cannot opt in.

Solution: Add a flat `[tui] notification_condition` setting (`unfocused`
by default, `always` opt-in), carry grouped TUI notification settings
through runtime config, apply method + condition together in the TUI,
and regenerate the config schema.

codex-rs/config/src/types.rs

@@ -472,6 +472,44 @@ impl fmt::Display for NotificationMethod {
     }
 }
 
+#[derive(Serialize, Deserialize, Debug, Clone, Copy, PartialEq, Eq, JsonSchema, Default)]
+#[serde(rename_all = "lowercase")]
+pub enum NotificationCondition {
+    /// Emit TUI notifications only while the terminal is unfocused.
+    #[default]
+    Unfocused,
+    /// Emit TUI notifications regardless of terminal focus.
+    Always,
+}
+
+impl fmt::Display for NotificationCondition {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            NotificationCondition::Unfocused => write!(f, "unfocused"),
+            NotificationCondition::Always => write!(f, "always"),
+        }
+    }
+}
+
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq, Default, JsonSchema)]
+#[schemars(deny_unknown_fields)]
+pub struct TuiNotificationSettings {
+    /// Enable desktop notifications from the TUI.
+    /// Defaults to `true`.
+    #[serde(default, rename = "notifications")]
+    pub notifications: Notifications,
+
+    /// Notification method to use for terminal notifications.
+    /// Defaults to `auto`.
+    #[serde(default, rename = "notification_method")]
+    pub method: NotificationMethod,
+
+    /// Controls whether TUI notifications are delivered only when the terminal is unfocused or
+    /// regardless of focus. Defaults to `unfocused`.
+    #[serde(default, rename = "notification_condition")]
+    pub condition: NotificationCondition,
+}
+
 #[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq, Default, JsonSchema)]
 #[schemars(deny_unknown_fields)]
 pub struct ModelAvailabilityNuxConfig {
@@ -484,15 +522,8 @@ pub struct ModelAvailabilityNuxConfig {
 #[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Default, JsonSchema)]
 #[schemars(deny_unknown_fields)]
 pub struct Tui {
-    /// Enable desktop notifications from the TUI when the terminal is unfocused.
-    /// Defaults to `true`.
-    #[serde(default)]
-    pub notifications: Notifications,
-
-    /// Notification method to use for unfocused terminal notifications.
-    /// Defaults to `auto`.
-    #[serde(default)]
-    pub notification_method: NotificationMethod,
+    #[serde(default, flatten)]
+    pub notification_settings: TuiNotificationSettings,
 
     /// Enable animations (welcome screen, shimmer effects, spinners).
     /// Defaults to `true`.