Add marketplace NIP-99 support

[alltheseas]

Gents, there are at least three nostr apps that have added support for NIP-99 marketplaces.

https://github.com/nostr-protocol/nips/blob/master/99.md

Below is linked a recent nostr talk on nostr marketplaces and includes a demo of how everything works:

Https://njump.me/nevent1qqs2wy4qkuutdwuetgt7qeaqknqq44v4f7xewrxuwwhhstsvcd68ncgpzemhxue69uhhyetvv9ujuurjd9kkzmpwdejhg6mfcd4

Marketplaces thus far are
Shopstr.store
Plebeian.market
Conduit.market

Would be awesome for SN to adopt NIP-99 marketplaces

[ekzyis]

Writing NIP-99 events

This could be implemented as a new item type that uses the existing nostr crossposting code to broadcast the item as a NIP-99 event.

However, our code for item types and nostr crossposting probably need an overhaul first.

Reading NIP-99 events

I don't see this happening without a huge redesign of almost everything to support external items in our feed.

The first question that comes to my mind is how this should interact with the pay-to-post nature of SN. There are no free posts on SN, but external items did not pay the territory founder.

[amunrarara]

Rock and roll @ekzyis,

We've been discussing internally on the Gamma Markets thread; pay-to-post is not yet in the spec, but it's a somewhat trivial task via pay-to-post relays. The spec could definitely be expanded to include that; I believe there's an existing NIP with subscription-based pay-to-post implemented, I'll have to do a lil' looky-looing.

If you'd like to discuss it, scope it out, and get some support from the team, you should join our Gamma Markets Signal thread. We'd love to have you!

[alltheseas]

@ekzyis markets signal chat group link: https://signal.group/#CjQKIO0jmW-Ir0eVPk1u4fPWionN3Ua9c9M-8aNk1lXNgrsGEhCvj9-DV1ykzbIWjWEbUMpn