feat(ui): Select Other — pick what lies under something else (#503)

Hold the left button still (long-press on touch) or right-click › Select Other… to list everything under the cursor: sketch points and curves ("Line 3", "Point (arc 2 centre)"), vertices, edges, faces, bodies, profiles, planes and axes, filtered like a click and by the open dialog's active input. Hovering a row lights it up; clicking selects it (Shift/Ctrl add) or feeds the dialog. A repeat click on the same spot with nothing changed selects the next thing there; a double-click keeps its own actions.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/ui-egui/src/control.rs

@@ -501,6 +501,7 @@ pub fn handle(app: &mut SolveApp, ctx: &egui::Context, req: &ControlRequest) ->
                 json!({"diagnostics": crate::help::diagnostics(app), "version": crate::help::VERSION, "commit": crate::help::COMMIT, "built": crate::help::BUILD_DATE}),
             ),
         },
+        "ui.selectOther" => wrap(crate::select_other::control(app, p)),
         "ui.menuPick" => {
             let Some(key) = s("item") else { return err("missing `item` (id or label)") };
             wrap(crate::context_menu::pick(app, key))