Application hide, download bounce, menu bar, about prose

1. ✅ When application is closed by hiding, it still thinks it has focus (so it marks any unread as read) — same if minimized 2. ☑️ Make Download folder bounce when download is done 3. ☑️ Menu bar for macOS (Settings + Profile buttons, Check for Updates et al) 4. ☑️ About Prose.app window for macOS (fill it with Prose website and details) progress 1. ✅ See if window is in focus (both web and Tauri) ```js UtilitiesRuntime.registerWindowFocusCallback((focus) => console.log("focus: " + focus)) ```