Add Set 17 · Matrix Moves — the atlas is finished

Matrices as index algebra: the redundancy killed is the O(mn) copy.
Rotate Image (transpose ∘ reflect derived as composed involutions,
strict-triangle proof), Spiral Matrix (four monotone boundaries with
the two-guard asymmetry proved), Set Zeroes (row-0/col-0 as flag
storage — why no sentinel can exist in an all-int domain), Game of
Life (bit-packed generations solving the simultaneity problem),
staircase search (a corner is a comparator, O(m+n)), and LC 329 as
the capstone boss: strictness ⇒ DAG ⇒ memoized DFS with no visited
set — three sets composing in one problem.

Atlas: 27/27. 7 ladder problems (incl. LC 59 re-solve), 6 flashcards
(deck: 110), interrogation M1-M5 with hint sketches, decision-tree
row 14. App totals: 153 sections, 124 ladder rungs, 92 journal Qs.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: DeepCodeWork