Ditto only supports Nostr zaps within Nostr. The only ActivityPub stuff I've even added to Ditto so far are actor endpoints. Ditto is actually just a Nostr community relay with Mastodon API support, and I'm still working out the basic product and functionality of that before I add true ActivityPub support. Which I might add as an optional microservice. The real utility of Ditto will be for ActivityPub people to use Nostr with all the apps they already use, and to attract moderated communities to Nostr on an infrastructure level instead of just a protocol level. They will be able to use the bridge to stay connected with ActivityPub in the first release of Ditto, until true support is added.