Now that we have Apps (kind 32267), the Application Handlers (Nip-89) thing becomes silly. Since it makes more sense to specify the content types an App supports **in the App publication** than anywhere else.

With this you could go beyond just Nostr content handling.

👉 Supported content types: kind 9, kind 30023, mp3, PDF, ...

For recommending Apps, it also makes more sense to recommend the Apps themselves, instead of a (now redundant and confusing) application handler event.