Add /api/aspa/{asn}/{peer} endpoint for peer authorization checks
Extends the JSON API with a route to check whether a given peer ASN is authorized as an upstream provider for a customer ASN, mirroring the existing peer-check already available on the HTML lookup page. Response is a superset of the existing /api/aspa/{asn} shape, adding peer and authorized fields.
Co-Authored-By: Claude Sonnet 5 noreply@anthropic.com Claude-Session: https://claude.ai/code/session_01SdWQ3jVyzwRoQjVfAfK4mZ