Review round 2 (Codex gpt-5.6-terra, 2 LOW): 2015-01-06 is a Tuesday,
not a Monday — the anchor is now the computed first Monday of January
(asserted weekday 0); the docstring names the ISO-week rollover
precisely (the Monday on or after January 4th — January 4th in both
walked years, which end ISO week 53) instead of 'January 1st'. Suite:
1005 passed.
Review round 1 (Codex gpt-5.6-terra, MEDIUM): the walk stopped at
December 31st, so the boundary block's next-January days went
unchecked and a year-resetting implementation would pass. The walk
now runs through January 14th of the following year, asserting block
uniformity across the December 31st -> January 1st transition
(including the post-53-week jump), and the walked-year day count is
verified independently of the walk. Suite: 1005 passed.
The week-parity regression test (D-004): walks a two-week alternating
rotation day by day across a FULL 366-day leap year (2020) and a full
365-day year with 53 ISO weeks (2015), asserting the present-day
sequence never breaks or inverts, including January 1st. The
expectation is derived from the anchor's 7-day blocks — each block
uniform, consecutive blocks alternating — not from the engine's own
index formula, so a parity-based implementation that resets on
January 1st breaks block uniformity or alternation (most visibly in
the block spanning the boundary). Year facts asserted: 2020 = 366
days and ISO week 53; 2015 = 365 days and ISO week 53. The test
docstring names itself as the regression guard. Suite: 1004 passed.
Joshua King