Your nip07/nostraddress is invalid. Suggest you set up a nostr well-known on your website and update your profile so people can trace your package signature on zap store to something you own like

The simplest self-custodial Bitcoin Lightning wallet—send, spend, and accept BTC.

Blitz Wallet is a fully open-source self-custodial Bitcoin and Lightning wallet that makes payments simple. Download the app, send money to friends...

.

Custom Nostr verification using github pages

owning your own verification on the cheap.

You can also sign a github gist from your github account using NIP39 proving your npub is tied to the developer of your app and paste the URL into your npub profile under "github gist with signature"

GitHub

nips/39.md at master · nostr-protocol/nips

Nostr Implementation Possibilities. Contribute to nostr-protocol/nips development by creating an account on GitHub.