fix: typos in model picker (#6859)

# External (non-OpenAI) Pull Request Requirements

Before opening this Pull Request, please read the dedicated
"Contributing" markdown file or your PR may be closed:
https://github.com/openai/codex/blob/main/docs/contributing.md

If your PR conforms to our contribution guidelines, replace this text
with a detailed and high quality description of your changes.

Include a link to a bug report or enhancement request.

codex-rs/tui/src/chatwidget/snapshots/codex_tui__chatwidget__tests__model_reasoning_selection_popup.snap

@@ -2,13 +2,11 @@
 source: tui/src/chatwidget/tests.rs
 expression: popup
 ---
-  Select Reasoning Level for gpt-5.1-codex
+  Select Reasoning Level for arcticfox
 
-  1. Low               Fastest responses with limited reasoning
-  2. Medium (default)  Dynamically adjusts reasoning based on the task
-› 3. High (current)    Maximizes reasoning depth for complex or ambiguous
-                       problems
-                       ⚠ High reasoning effort can quickly consume Plus plan
-                       rate limits.
+  1. Low               Fast responses with lighter reasoning
+  2. Medium (default)  Balances speed and reasoning depth for everyday tasks
+› 3. High (current)    Maximizes reasoning depth for complex problems
+  4. Extra high        Extra high reasoning depth for complex problems
 
   Press enter to confirm or esc to go back

codex-rs/tui/src/chatwidget/snapshots/codex_tui__chatwidget__tests__model_reasoning_selection_popup_extra_high_warning.snap

@@ -0,0 +1,16 @@
+---
+source: tui/src/chatwidget/tests.rs
+assertion_line: 1548
+expression: popup
+---
+  Select Reasoning Level for arcticfox
+
+  1. Low                   Fast responses with lighter reasoning
+  2. Medium (default)      Balances speed and reasoning depth for everyday
+                           tasks
+  3. High                  Maximizes reasoning depth for complex problems
+› 4. Extra high (current)  Extra high reasoning depth for complex problems
+                           ⚠ Extra high reasoning effort can quickly consume
+                           Plus plan rate limits.
+
+  Press enter to confirm or esc to go back

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

@@ -1526,19 +1526,59 @@ fn startup_prompts_for_windows_sandbox_when_agent_requested() {
 fn model_reasoning_selection_popup_snapshot() {
     let (mut chat, _rx, _op_rx) = make_chatwidget_manual();
 
-    chat.config.model = "gpt-5.1-codex".to_string();
+    chat.config.model = "arcticfox".to_string();
     chat.config.model_reasoning_effort = Some(ReasoningEffortConfig::High);
 
     let preset = builtin_model_presets(None)
         .into_iter()
-        .find(|preset| preset.model == "gpt-5.1-codex")
-        .expect("gpt-5.1-codex preset");
+        .find(|preset| preset.model == "arcticfox")
+        .expect("arcticfox preset");
     chat.open_reasoning_popup(preset);
 
     let popup = render_bottom_popup(&chat, 80);
     assert_snapshot!("model_reasoning_selection_popup", popup);
 }
 
+#[test]
+fn model_reasoning_selection_popup_extra_high_warning_snapshot() {
+    let (mut chat, _rx, _op_rx) = make_chatwidget_manual();
+
+    chat.config.model = "arcticfox".to_string();
+    chat.config.model_reasoning_effort = Some(ReasoningEffortConfig::XHigh);
+
+    let preset = builtin_model_presets(None)
+        .into_iter()
+        .find(|preset| preset.model == "arcticfox")
+        .expect("arcticfox preset");
+    chat.open_reasoning_popup(preset);
+
+    let popup = render_bottom_popup(&chat, 80);
+    assert_snapshot!("model_reasoning_selection_popup_extra_high_warning", popup);
+}
+
+#[test]
+fn reasoning_popup_shows_extra_high_with_space() {
+    let (mut chat, _rx, _op_rx) = make_chatwidget_manual();
+
+    chat.config.model = "arcticfox".to_string();
+
+    let preset = builtin_model_presets(None)
+        .into_iter()
+        .find(|preset| preset.model == "arcticfox")
+        .expect("arcticfox preset");
+    chat.open_reasoning_popup(preset);
+
+    let popup = render_bottom_popup(&chat, 120);
+    assert!(
+        popup.contains("Extra high"),
+        "expected popup to include 'Extra high'; popup: {popup}"
+    );
+    assert!(
+        !popup.contains("Extrahigh"),
+        "expected popup not to include 'Extrahigh'; popup: {popup}"
+    );
+}
+
 #[test]
 fn single_reasoning_option_skips_selection() {
     let (mut chat, mut rx, _op_rx) = make_chatwidget_manual();
@@ -1556,6 +1596,7 @@ fn single_reasoning_option_skips_selection() {
         supported_reasoning_efforts: &SINGLE_EFFORT,
         is_default: false,
         upgrade: None,
+        show_in_picker: true,
     };
     chat.open_reasoning_popup(preset);