Lowercase the retry hint for conversations open in another app (#47112)

Change `R to Retry` to `r to retry` in the TUI notice and update the
corresponding rendering snapshots.

GitOrigin-RevId: f7971ba0f76ac446a5fea53b44390f65aa965be4

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

@@ -64,8 +64,8 @@ impl ExternalWriterNotice {
         ]
         .into();
         let retry: Line<'static> = vec![
-            Span::styled("R", crate::style::accent_style()),
-            " to Retry".into(),
+            Span::styled("r", crate::style::accent_style()),
+            " to retry".into(),
         ]
         .into();
         let mut lines = word_wrap_lines(&[title], usize::from(width));

codex-rs/tui/src/chatwidget/snapshots/codex_tui__chatwidget__rendering__tests__external_writer_command_center_100.snap

@@ -4,7 +4,7 @@ expression: rendered
 ---
 
 
-  🔒   This conversation is open in another app                                          R to Retry
+  🔒   This conversation is open in another app                                          r to retry
       Close it there and press R to continue here.
 
    r retry   esc command center   ctrl+c/q exit   ctrl+t transcript

codex-rs/tui/src/chatwidget/snapshots/codex_tui__chatwidget__rendering__tests__external_writer_command_center_60.snap

@@ -4,7 +4,7 @@ expression: rendered
 ---
 
 
-  🔒   This conversation is open in another app  R to Retry
+  🔒   This conversation is open in another app  r to retry
       Close it there and press R to continue here.
 
    r retry   esc command center   ctrl+c/q exit   ctrl+t

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

@@ -4,7 +4,7 @@ expression: "rows.iter().map(|row| row.trim_end()).collect::<Vec<_>>().join(\"\\
 ---
 
 
-  🔒   This conversation is open in another app  R to Retry
+  🔒   This conversation is open in another app  r to retry
       Close it there and press R to continue here.
 
    r retry   esc/ctrl+c/q exit   ctrl+t transcript

codex-rs/tui/src/snapshots/codex_tui__app__agents_overview__tests__agents_overview_attach_conflict.snap

@@ -2,7 +2,7 @@
 source: tui/src/app/agents_overview_tests.rs
 expression: "render_bottom_popup(&app.chat_widget, 96)"
 ---
-  🔒   This conversation is open in another app                                      R to Retry
+  🔒   This conversation is open in another app                                      r to retry
       Close it there and press R to continue here.
 
    r retry   esc command center   ctrl+c/q exit   ctrl+t transcript