Fix M2: clamp picksplit nBins to nTuples to prevent out-of-bounds
read on the entries array when called with a single tuple.
Fix H2: use WGS72_AE as effective bin_low for the first bin in L0
inner_consistent, preventing false negatives when objects with lower
SMA than the first label are inserted after index creation.
Fix H3: reject degenerate TLEs (mean_motion <= 0) early in the
visibility filter rather than propagating nonsensical values.
Fix L1: extract shared tle_passes_visibility_filter() to eliminate
duplicated 3-stage filter logic between leaf_consistent and the
standalone tle_visibility_possible operator.
Add boundary tests: degenerate TLE, polar observer, zero-duration
window, and post-insert index-vs-seqscan consistency check.
Ryan Malloy
2a7240e739