Could you build your own tap-to-pay app nostr:nprofile1qqs8xgquvj09ymv7a09fzd574rsp0sdlm75k87pwg3qsa4n0dhz20mgpzpmhxue69uhkummnw3ezumrpdejqz9rhwden5te0wfjkccte9ejxzmt4wvhxjmcfcsehn