ui: add banners to profile previews

profile previews still need lots of work, but this was a challenge to
get an aspectRatio: fill mechanism for images which the banner takes
advantage of.

Signed-off-by: William Casarin <jb55@jb55.com>

src/ui/note/contents.rs

@@ -139,6 +139,7 @@ fn render_note_contents(
                             if let Some(rec) = profile.as_ref() {
                                 resp.on_hover_ui_at_pointer(|ui| {
                                     egui::Frame::default().show(ui, |ui| {
+                                        ui.set_max_width(300.0);
                                         ui.add(ui::ProfilePreview::new(rec));
                                     });
                                 });