Auto-updating or at least update notification

We can offer to automatically update or at least we can show a notification when a new version is published.  Tauri has a [plugin for updating](https://tauri.app/plugin/updater/) that [opencode use](https://github.com/anomalyco/opencode/blob/a58d1be8226c749f015047c15c47950735cd9370/packages/desktop/src-tauri/tauri.prod.conf.json#L48-L52) too.