Preferences: one Fusion-style dialog from the gear at the top right and Ctrl+, (Cmd+,)

Pages: General (theme Dark/Light/System, UI scale, units of new designs, autosave, display
precision, the agent cursor), Navigation (Fusion, SolidWorks, Inventor, Alias and Tinkercad
mouse presets, reverse zoom, zoom to the cursor, orbit centre, view-change animation on/off and
speed), Keyboard Shortcuts (the old Shortcuts window as a page: search, rebind, conflicts),
Design (default modelling orientation Y up / Z up for #3, and the offer to stand up a Y-up STEP
or IGES file: a quarter turn about X as one undoable Move), Graphics, Sketch, Selection.
Changes apply at once; Cancel or Esc puts back what was there when the dialog opened, Apply
keeps them, OK closes, Restore Defaults resets the page. The theme, ground shadow and agent
cursor settings are now kept between runs. File and Help › Keyboard Shortcuts open the page;
the unused docked Preferences dialog is gone. Control: ui.prefs {open, button, stand_up, …}.
Scenario s45_preferences; tests for Cancel/Apply/defaults and standing a Y-up file up.

Fixes #36

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RjGw4gA5ZvKrU8MQP6sBgT

crates/ui-egui/src/viewport.rs

@@ -1292,7 +1292,8 @@ pub fn show(app: &mut SolveApp, ui: &mut egui::Ui) {
     let h = rect.height().max(1.0) as f64;
     if inside && scroll != 0.0 {
         let f = (-scroll as f64 * 0.0015 * crate::prefs::zoom_sign(app)).exp();
-        let anchor = hover.map(|p| {
+        // Preferences › Navigation › Zoom to the cursor (off: toward the view's centre).
+        let anchor = hover.filter(|_| app.preferences.zoom_to_cursor).map(|p| {
             let proj = projection(app, rect);
             // Toward the model's surface under the cursor, else the target's depth.
             if let Some(q) = pick_cached(app, &proj, p).iter().find_map(|h| if let Hit::Face { point, .. } = h { Some(*point) } else { None }) {