gpconf: a conformance corpus for orbital-data parsers crossing the five-digit catalog-number boundary

Expected values, structural checks, specification vectors, derived Alpha-5 TLE sets and a standard-library runner that test whether an orbital-data parser handles the 2026 migration of the US satellite catalog past five-digit numbers: Alpha-5 encoding, six- and nine-digit catalog numbers, and the CCSDS Orbit Mean-Elements Message in CSV, JSON, XML and KVN as served by CelesTrak. No provider data is redistributed, and one provider response is, the 16-byte answer "No GP data found"; a fetch script rebuilds the data locally under the provider's terms and SHA-256 hashes identify the tested snapshot. Built with AI assistance under human direction; v0.1.0 was audited by a separate AI session with no access to the build context (AUDIT.md); decision log in DECISIONS.md.