Add upstream test vectors: 42 OEM tests, CDM Blue Book examples
ocaml-odm: 52 tests total (was 10)
- 10 v2.0 valid KVN samples from bradsease/oem
- 8 real orbit samples (LEO/MEO/GEO at 10s/20s/60s intervals)
- 22 invalid samples (crash safety)
- LEO altitude/velocity range checks
- GEO altitude/velocity range checks
- Covariance block skipping (COVARIANCE_START/STOP)
ocaml-cdm: Blue Book section 4 KVN + XML test vectors archived