make_knots_compatible: checked start indices (degree i64::MAX panicked);
check_index: checked p + 1.
ffi/shim: make_compatible_reads_in_bounds replays N_MakeKnotsCompatible's
rescale and index walk and rejects exactly the inputs that read past
R[mr]/S[ms] (UB-13); difftest compares them as read_past_end on both sides.
Regression fixtures in fixtures/nlib.basis_basic/fuzz_regressions.json.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Andreas