Census of trapped steps on surviving block paths (fourier_wren, 2 Nov 2026).
Run from a directory containing notes/counting/expo/ with these files, or edit the sys.path lines.
  python chain_census.py M B    -> all odd b < 2^B at conductor m = M, r = M//8 blocks.
trapped_table (deep_occ.py) uses exact integer residues: T[t,A] is true iff
  |centered(b * 3^-(A+7) mod 2^(m-6-4t))| * 7938 <= 2^(m-6-4t).
best_trapped is a max-plus DP over sequences n_0 = 0, n_(t+1) - n_t in {0..4}, 3^(n_t) > 16^t.
Outputs: chain_census_<m>.txt (top 12 b and the histogram of the maximum).
wtail.py is imported by deep_occ.py but only its helper functions are loaded; it is not used by the census.
