test(parity): rebaseline v1.57.7.0 → v1.64.1.0 + skeleton-cap headroom

The two parallel v1.64 waves (code-smell fix wave + main's #2571) each
added shared-preamble prose, pushing document-release / design-consultation
/ cso past their size ratios on the v1.57.7.0 anchor and four carved
skeletons (plan-ceo-review, plan-eng-review, office-hours,
design-consultation) 22-280 B over their absolute caps. New baseline is
union-normalized (skeleton + sections/*.md, matching what the harness
measures); caps get +~1 KB headroom each with per-cap rationale. The
v1.57.7.0 fixture stays in test/fixtures/ for the audit trail, and
capture-parity-baseline.ts now documents the union-normalization step so
the next rebaseline doesn't re-trip on it.

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

test/helpers/capture-parity-baseline.ts

@@ -22,6 +22,14 @@ import { execSync } from 'child_process';
 
 export interface SkillBaselineEntry {
   skill: string;
+  /**
+   * SKILL.md file bytes as captured. NOTE for rebaselines: the parity harness
+   * compares UNION bytes (skeleton + sections/*.md) against this field, so a
+   * committed baseline fixture must have carved skills' entries normalized to
+   * union size (skeleton + sum of sections/*.md) or every carved skill reads
+   * as 1.2-1.4x over on day one. The v1.57.7.0 and v1.64.1.0 fixtures are
+   * union-normalized.
+   */
   skillMdBytes: number;
   skillMdLines: number;
   estTokens: number; // ~4 chars/token heuristic