feat: enhance UI for active tabs and settings dialog

- Active Tab: Now uses `FontWeight::BOLD`, `text_base()` font size, and the primary theme color. This makes it far more distinct from inactive tabs, especially in themes where background differences are subtle.
- Settings Dialog: Overrode the default sidebar style to use the main dialog background (`cx.theme().background`), seamlessly blending the sidebar with the content pane.
- Refactor: Renamed unused `_cx` parameter to `cx` in the settings dialog render closure since it is now being utilized to access the theme.

src/app/dialogs.rs

@@ -871,7 +871,7 @@ impl Ashell {
                 .h(px(560.))
                 .content({
                     let view = view.clone();
-                    move |content, _window, _cx| {
+                    move |content, _window, cx| {
                         use gpui_component::setting::{Settings, SettingPage, SettingGroup, SettingItem, SettingField};
                         use gpui::IntoElement;
                         let version = env!("CARGO_PKG_VERSION");
@@ -880,6 +880,7 @@ impl Ashell {
                         content.child(
                             Settings::new("settings")
                                 .sidebar_width(px(180.))
+                                .sidebar_style(div().bg(cx.theme().background).style())
                                 .page(
                                     SettingPage::new(t!("settings_general").to_string())
                                         .icon(IconName::Settings)

src/app/ui.rs

@@ -1470,7 +1470,15 @@ impl Ashell {
                                                         .h(px(32.))
                                                         .bg(dot_color),
                                                 )
-                                                .label(label)
+                                                .child(
+                                                    div()
+                                                        .when(ix == selected, |this| {
+                                                            this.font_weight(FontWeight::BOLD)
+                                                                .text_color(cx.theme().primary)
+                                                                .text_base()
+                                                        })
+                                                        .child(label),
+                                                )
                                                 .on_click(cx.listener(
                                                     move |this, _, window, cx| {
                                                         this.activate_group(