6 custom types (tle, eci_position, geodetic, topocentric, observer,
pass_event), 67 SQL functions, 2 operators (&&, <->), and a GiST
operator class for altitude-band indexing. Wraps Bill Gray's sat_code
for SGP4/SDP4 propagation with WGS-72 constants for propagation and
WGS-84 for coordinate output. All 5 regression tests pass on PG 18.
