Use ⌥⇧⌃ glyphs for key hints on mac (#3143)

#### Summary
- render the edit queued message shortcut with the ⌥ modifier on macOS
builds
- add a helper for status indicator snapshot suffixes
- record macOS-specific snapshots for the status indicator widget

codex-rs/tui/src/key_hint.rs

@@ -0,0 +1,49 @@
+use ratatui::style::Color;
+use ratatui::style::Style;
+use ratatui::text::Span;
+use std::fmt::Display;
+
+#[cfg(test)]
+const ALT_PREFIX: &str = "⌥";
+#[cfg(all(not(test), target_os = "macos"))]
+const ALT_PREFIX: &str = "⌥";
+#[cfg(all(not(test), not(target_os = "macos")))]
+const ALT_PREFIX: &str = "Alt+";
+
+#[cfg(test)]
+const CTRL_PREFIX: &str = "⌃";
+#[cfg(all(not(test), target_os = "macos"))]
+const CTRL_PREFIX: &str = "⌃";
+#[cfg(all(not(test), not(target_os = "macos")))]
+const CTRL_PREFIX: &str = "Ctrl+";
+
+#[cfg(test)]
+const SHIFT_PREFIX: &str = "⇧";
+#[cfg(all(not(test), target_os = "macos"))]
+const SHIFT_PREFIX: &str = "⇧";
+#[cfg(all(not(test), not(target_os = "macos")))]
+const SHIFT_PREFIX: &str = "Shift+";
+
+fn key_hint_style() -> Style {
+    Style::default().fg(Color::Cyan)
+}
+
+fn modifier_span(prefix: &str, key: impl Display) -> Span<'static> {
+    Span::styled(format!("{prefix}{key}"), key_hint_style())
+}
+
+pub(crate) fn ctrl(key: impl Display) -> Span<'static> {
+    modifier_span(CTRL_PREFIX, key)
+}
+
+pub(crate) fn alt(key: impl Display) -> Span<'static> {
+    modifier_span(ALT_PREFIX, key)
+}
+
+pub(crate) fn shift(key: impl Display) -> Span<'static> {
+    modifier_span(SHIFT_PREFIX, key)
+}
+
+pub(crate) fn plain(key: impl Display) -> Span<'static> {
+    Span::styled(format!("{key}"), key_hint_style())
+}