1bd91dbbb9
Addresses PR review: the containing block for an absolutely-positioned child is the **padding box** (inside the borders), not the "border-box". Verified by running yoga (an abs child at top:0/left:0 insets by the border only, never by padding — confirmed across border/padding combos) and the real Ink/vue-tui renderers (X lands at the inner-border edge, byte-identical in both). - Tighten the regression test: exact-frame assertions instead of `toContain`, including a border+padding case that distinguishes the padding box from the content box — the assertion that would have caught the original wording slip (presence-only assertions could not). - Correct "containing block (border-box)" -> "padding box (inside the borders)" in paint.ts, layout-guards.ts, and ink-divergences.md. (The unrelated "border-box-like" *sizing* notes are correct and left as-is.) No runtime behavior change; the code already used yoga's computed position. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>