Avoid false matches in permissions popup helper

Match the selected permissions preset by the row name prefix instead of a loose substring search so the Smart Approvals description cannot masquerade as Default during popup navigation.

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

.codex/flaky-test-triage.md

@@ -49,6 +49,7 @@ Older failures also appeared on Linux, but the repeated cross-PR signal is stron
 - Make the generic permissions-popup helper recognize `Read Only`, which is a real preset on Windows.
 - Replace Windows-specific hard-coded navigation counts with label-driven movement in the permission history snapshot tests.
 - Replace the remaining Windows-only extra navigation in the full-access confirmation/history test, and use the same label-driven movement in the adjacent Smart Approvals popup tests.
+- Follow-up on `87941e5d7`: the helper compared the entire selected row with `contains(label)`, which made `Smart Approvals` look like `Default` because its description text says "Same workspace-write permissions as Default...". Tighten the helper to match the selected preset name at the start of the row instead of any substring in the rendered line.
 - Rationale: commit `e96d895c9` still failed on both Windows `Tests` jobs in run `23080608881`. The remaining common pattern is Windows-only popup navigation that assumes a fixed number of `Up`/`Down` presses even though the Windows menu includes `Read Only` and selection wraps.
 
 ## Constraints

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

@@ -6615,10 +6615,26 @@ fn selected_permissions_popup_line(popup: &str) -> &str {
         })
 }
 
+fn selected_permissions_popup_name(popup: &str) -> &'static str {
+    selected_permissions_popup_line(popup)
+        .trim_start()
+        .strip_prefix('›')
+        .map(str::trim_start)
+        .and_then(|line| line.split_once(". ").map(|(_, rest)| rest))
+        .and_then(|line| {
+            ["Read Only", "Default", "Smart Approvals", "Full Access"]
+                .into_iter()
+                .find(|label| line.starts_with(label))
+        })
+        .unwrap_or_else(|| {
+            panic!("expected permissions popup row to start with a preset label: {popup}")
+        })
+}
+
 fn move_permissions_popup_selection_to(chat: &mut ChatWidget, label: &str, direction: KeyCode) {
     for _ in 0..4 {
         let popup = render_bottom_popup(chat, 120);
-        if selected_permissions_popup_line(&popup).contains(label) {
+        if selected_permissions_popup_name(&popup) == label {
             return;
         }
         chat.handle_key_event(KeyEvent::from(direction));