Browser: rows out of view take only their space (400 bodies: 1.95 ms to 0.72 ms per frame, docs/perf.md); V shows/hides what is selected (bodies, sketches, planes and axes, components, canvases), Show/Hide with V in every menu that has it

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AS5Tn3xieewUSg3uxrMVdL

crates/ui-egui/src/toolbar.rs

@@ -434,6 +434,7 @@ pub fn shortcuts(app: &mut SolveApp, ctx: &egui::Context) {
                 }
             }
             Key::S => app.ui.palette_open = true,
+            Key::V => crate::context_menu::toggle_visibility(app),
             Key::F6 => app.animate_view("fit"),
             Key::Delete | Key::Backspace => crate::viewport::delete_selection(app),
             _ => {