New: section 6 of papers/odd_parity_sector.md — the near-null branches of
both parity blocks at c = 100. Across twelve cell-sector combinations the
number of roots a branch produces beyond the tested ordinates is
non-decreasing in |lambda|, with the sign of the eigenvalue interleaved
throughout and no separate sign effect detected. The negative eigenvalues
of those blocks are counted against the archimedean cutoff, and a
parity-count pattern that held in five successive cells is reported
together with the sixth cell that breaks it.
New: harness/negative_branch.py, harness/root_precision_probe.py.