tasselx/Keyden ? reverse-engineered prompt

Build me a clean macOS menu bar app for TOTP codes.

I want it to keep all my 2FA secrets safely in the Mac keychain, let me add accounts by scanning a QR code or typing the secret in manually, and show the current codes right from the menu bar. Clicking a code should copy it straight to the clipboard. It should also support importing and exporting multiple accounts, grouping them nicely, pinning favorites, and reordering them.

Please make it feel polished and simple, with light and dark mode that follows the system, a global keyboard shortcut to open it quickly, and an option to launch at login. If it makes sense, add optional sync through a private GitHub Gist, but keep the app fully usable offline. A small command line tool for getting and listing codes would be great too. If you need to look up any current Apple or Swift docs, go ahead and do that.