yoda: toolbar icon-only + clean visual (Control style, 32px squares)

User feedback: segmented visual was noisy; only want icons, no labels.

Changes:
- rebuild_toolbar_model no longer sets .text() on entities, so the
  segmented_button widget draws icon-only squares.
- toolbar renders with style(SegmentedButton::Control), button_height
  + min/max_button_width pinned at 32 px (square icon buttons),
  button_spacing = space_xs for clear separation (was space_xxs which
  looked conjoined), Alignment::Center.
- container width = Length::Shrink so the toolbar only takes the space
  it needs instead of stretching across the window.

src/app.rs

@@ -1827,14 +1827,17 @@ impl App {
     /// Called on init and on every config update. Each entity carries the
     /// associated `ToolbarAction` as data so click/reorder handlers can
     /// round-trip Entity → ToolbarAction without maintaining a side map.
+    ///
+    /// We insert ONLY the icon (no `.text()`) so the toolbar renders as a
+    /// clean icon row — user-visible labels stay in Settings/tooltips on
+    /// other surfaces.
     fn rebuild_toolbar_model(&mut self) {
         self.toolbar_model.clear();
         for action in self.config.toolbar.iter().copied() {
-            let (icon_name, label, _msg) = toolbar_action_ui(action);
+            let (icon_name, _label, _msg) = toolbar_action_ui(action);
             self.toolbar_model
                 .insert()
                 .icon(widget::icon::from_name(icon_name).size(16).icon())
-                .text(label)
                 .data::<ToolbarAction>(action);
         }
     }
@@ -6833,7 +6836,7 @@ impl Application for App {
     /// Creates a view after each update.
     fn view(&self) -> Element<'_, Self::Message> {
         let cosmic_theme::Spacing {
-            space_xxs, space_s, ..
+            space_xxs, space_xs, space_s, ..
         } = theme::active().cosmic().spacing;
 
         let mut tab_column = widget::column::with_capacity(4);
@@ -6885,18 +6888,24 @@ impl Application for App {
         // ToolbarAction's message). Drag past threshold = reorder
         // (ToolbarTabReorder → model.reorder + sync to config).
         if !self.config.toolbar.is_empty() {
+            // Use Control style (no TabBar underline, no bottom border)
+            // and let each button shrink to its icon. Spacing = space_xs
+            // keeps the buttons visually separated so it looks like an
+            // icon toolbar rather than a conjoined segmented control.
             let toolbar = widget::segmented_button::horizontal(&self.toolbar_model)
+                .style(theme::SegmentedButton::Control)
                 .button_height(32)
-                .button_spacing(space_xxs)
-                .minimum_button_width(36)
-                .maximum_button_width(36)
+                .button_spacing(space_xs)
+                .button_alignment(Alignment::Center)
+                .minimum_button_width(32)
+                .maximum_button_width(32)
                 .enable_tab_drag(String::from("x-cosmic-files/toolbar-dnd"))
                 .on_reorder(Message::ToolbarTabReorder)
                 .tab_drag_threshold(8.)
                 .on_activate(Message::ToolbarTabActivate);
             tab_column = tab_column.push(
                 widget::container(toolbar)
-                    .width(Length::Fill)
+                    .width(Length::Shrink)
                     .padding([space_xxs, space_s]),
             );
         }