Keep Open and Save asynchronous to prevent macOS resize crashes (#1127)

Open and Save use parented AsyncFileDialog sheets; their answers run on the UI thread in a later frame, so resizing the window while a picker is open no longer re-enters winit and aborts. Editors, tab changes, Close/Quit and model-changing control requests wait for the answer; the local library Open and Export in the Appearance dialog use the same flow. Fixes #1088.

crates/ui-egui/src/keymap.rs

@@ -256,18 +256,21 @@ pub fn page(app: &mut SolveApp, ui: &mut egui::Ui) {
         Some((_, "reset_all")) => reset(app, None),
         Some((_, "export")) => {
             let text = crate::toolbar_custom::export(app).to_string();
-            if let Some(path) = app.services.pick_save.as_ref().and_then(|f| f("SolidCraft shortcuts.json", &["json"])) {
-                app.keymap.message = std::fs::write(&path, text).err().map(|e| format!("export: {e}"));
-            }
+            app.pick_save("SolidCraft shortcuts.json", &["json"], move |app, path| {
+                if let Some(path) = path {
+                    app.keymap.message = std::fs::write(&path, text).err().map(|e| format!("export: {e}"));
+                }
+            });
         }
         Some((_, "import")) => {
-            if let Some(path) = app.services.pick_open.as_ref().and_then(|f| f()) {
+            app.pick_open(|app, path| {
+                let Some(path) = path else { return };
                 let r = std::fs::read_to_string(&path)
                     .map_err(|e| e.to_string())
                     .and_then(|t| serde_json::from_str::<Value>(&t).map_err(|e| e.to_string()))
                     .and_then(|v| crate::toolbar_custom::import(app, &v));
                 app.keymap.message = r.err().map(|e| format!("import: {e}"));
-            }
+            });
         }
         Some((pair, "replace")) => {
             if let Some((id, key)) = pair.split_once('\n') {