Remove the SETUP card: the browser tree shows the progress

The setup checklist card (#265), its show_setup view setting, the View
menu checkbox and the preferences file that only remembered it go; the
tree's marks and ghost rows replace them. Session::progress and
model.check's progress stay for agents. An old prefs.json is no longer
read.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UhhZMBTviDQxZvwnyP89fo

crates/ui-egui/src/browser.rs

@@ -525,7 +525,6 @@ pub fn browser(app: &mut ModelApp, ui: &mut egui::Ui) {
         .frame(egui::Frame::NONE.fill(t.panel).inner_margin(egui::Margin::symmetric(6, 6)))
         .show(ui, |ui| {
             app.place("browser", ui.max_rect());
-            crate::setup::card(app, ui);
             ui.label(RichText::new("BROWSER").font(crate::theme::label_font(ui.ctx(), 10.5)).color(t.text_dim));
             ui.add_space(4.0);
             egui::ScrollArea::vertical().id_salt("fc_browser_scroll").auto_shrink([false, false]).show(ui, |ui| {