fix(desktop): await WebView recovery cleanup

Drive WebView recovery restart cleanup on the Tauri async runtime.

Mark shutdown clean and request restart only after cleanup completes.

Reuse the unified desktop exit flow for recovery dialog exits.

Author: wsp1911

src/apps/desktop/src/webview_recovery.rs

@@ -239,10 +239,7 @@ mod windows {
 
     fn request_automatic_restart(app: &tauri::AppHandle) {
         log::warn!("Requesting controlled application restart for WebView2 recovery");
-        crate::crash_diagnostics::mark_clean_shutdown("webview_recovery_restart");
-        crate::save_main_window_state(app, "webview_recovery_restart");
-        crate::perform_process_exit_cleanup();
-        app.request_restart();
+        request_controlled_restart(app, "webview_recovery_restart");
     }
 
     fn show_escape_dialog(app: tauri::AppHandle) {
@@ -265,19 +262,27 @@ mod windows {
                     request_user_restart(&app)
                 }
                 _ => {
-                    crate::crash_diagnostics::mark_clean_shutdown("webview_recovery_exit");
-                    crate::save_main_window_state(&app, "webview_recovery_exit_dialog");
-                    crate::perform_process_exit_cleanup();
-                    app.exit(1);
+                    crate::request_desktop_exit(&app, 1, "webview_recovery_exit");
                 }
             });
     }
 
     fn request_user_restart(app: &tauri::AppHandle) {
-        crate::crash_diagnostics::mark_clean_shutdown("webview_recovery_user_restart");
-        crate::save_main_window_state(app, "webview_recovery_user_restart");
-        crate::perform_process_exit_cleanup();
-        app.request_restart();
+        request_controlled_restart(app, "webview_recovery_user_restart");
+    }
+
+    fn request_controlled_restart(app: &tauri::AppHandle, reason: &'static str) {
+        crate::save_main_window_state(app, reason);
+        let app = app.clone();
+        tauri::async_runtime::spawn(async move {
+            crate::perform_process_exit_cleanup().await;
+            crate::crash_diagnostics::mark_clean_shutdown(reason);
+            log::info!(
+                "Desktop restart authorized after graceful shutdown: reason={}",
+                reason
+            );
+            app.request_restart();
+        });
     }
 
     fn map_failure_kind(kind: COREWEBVIEW2_PROCESS_FAILED_KIND) -> FailureKind {