[ HumanjavaEnterprises/nostr-auth-middleware ] fix: use undefined instead of false for corsOrigins type compatibility

The NostrConfig type allows string[] | "*" | undefined for corsOrigins,
but the fallback was set to false which caused a TypeScript build error.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
https://github.com/HumanjavaEnterprises/nostr-auth-middleware/commit/ac66a50f15663c24f28e8dcd882d77073e904e79