Range rate: topocentric residuals now include an optional 4th component
(dot(Δr, v_ecef) / |Δr|) with OD_RR_SCALE=10.0 for unit balancing.
Controlled via fit_range_rate parameter on tle_from_topocentric().
Weighted observations: per-observation weights applied as √w scaling
to both residuals and Jacobian rows, producing the weighted normal
equations H'WH without explicit W construction. Weights parameter
added to tle_from_eci, tle_from_topocentric, and tle_from_angles.
Gauss angles-only IOD: Vallado Algorithm 52 implementation for
seed-free orbit recovery from 3+ RA/Dec observations. New RA/Dec
residual function with cos(dec) scaling and wrap-around handling.
New tle_from_angles() and tle_from_angles_multi() SQL functions
accepting RA in hours [0,24), Dec in degrees [-90,90].
New standalone test suite: test_od_gauss (17 assertions).
New regression tests: Tests 18-25 covering range rate, weights,
angles-only with/without seed, and error cases.
Eliminates the seed TLE requirement for topocentric fitting by
computing an initial orbit estimate from 3 well-spaced observations
using the Gibbs method. ECI fitting retains the single-observation
r,v approach (exact for two-body) with Gibbs as fallback.
