how do bitchat dms over nostr work? are there any files in the codebase i can look into? nostr:nprofile1qqs9pk20ctv9srrg9vr354p03v0rrgsqkpggh2u45va77zz4mu5p6ccpz4mhxue69uhhyetvv9ujuerpd46hxtnfduhsz9nhwden5te0v4jx2m3wdehhxarj9ekxzmny9udktm2s or anyone