fix: use reverse video for TUI highlight style (closes #139) (#146)

Replace bg(Color::DarkGray) with Modifier::REVERSED in highlight_style
so the selected-row highlight adapts to both light and dark terminal themes.

Co-authored-by: jpoehnelt-bot <jpoehnelt-bot@users.noreply.github.com>

.changeset/fix-light-theme-highlight.md

@@ -0,0 +1,5 @@
+---
+"@googleworkspace/cli": patch
+---
+
+Fix highlight color on light terminal themes by using reverse video instead of a dark-gray background

src/setup_tui.rs

@@ -405,11 +405,7 @@ fn run_picker_loop(
                 .collect();
 
             let list = List::new(items)
-                .highlight_style(
-                    Style::default()
-                        .bg(Color::DarkGray)
-                        .add_modifier(Modifier::BOLD),
-                )
+                .highlight_style(Style::default().add_modifier(Modifier::REVERSED | Modifier::BOLD))
                 .highlight_symbol("▸ ");
 
             frame.render_stateful_widget(list, chunks[1], &mut state.list_state);
@@ -806,11 +802,7 @@ impl SetupWizard {
                     .borders(Borders::ALL)
                     .border_style(Style::default().fg(Color::DarkGray)),
             )
-            .highlight_style(
-                Style::default()
-                    .bg(Color::DarkGray)
-                    .add_modifier(Modifier::BOLD),
-            )
+            .highlight_style(Style::default().add_modifier(Modifier::REVERSED | Modifier::BOLD))
             .highlight_symbol("▸ ");
 
         frame.render_stateful_widget(list, area, &mut picker.list_state);