feat(rebar): 상면 주철근 단 간격(세로) 입력 100 mm, 가로는 2d 고정

- 세로 단 간격은 입력(기본 100, 범위 80–120)으로 상면 C1–C6, C14 상면, 기둥 C3 높이에 쓴다
- 가로 단 간격은 2d(H29, 57.2 mm)로 고정 (코핑철근.md의 s_lay 하나를 둘로 나눔)
- P1 기준 값 갱신: 상면 높이 43.284 / 43.184 / 43.084, C14 상면 43.208 / 43.108, P1 위 끝 zTop1 14776

Co-Authored-By: Claude Haiku 5.5 <noreply@anthropic.com>

src/core/rebar/summary.ts

@@ -200,7 +200,7 @@ export function rebarSummary(
   rows.push({ member: 'coping', name: 'C13', size: 'H25', count: 4 * side.c13.length, length: null, pieces: sidePieces(side.c13), note: `측면, 끝면까지, 일자 (${2 * side.c13.length}) · ㄷ ${Math.round(hook)} (${2 * side.c13.length})` });
   // C14 / C15 / C16 are derived from the model (코핑철근.md §7–8); the document's 38 / 11 / 22 and 3852 / 4070 / 4069 are checked in the tests.
   const L14 = model.copingL * 1000;
-  const c14 = c14Bars(L14, model.copingRefTop, [...side.c12, ...side.c13], (x) => undersideAt(L14, x, model.endBottom, model.levelBottom, model.copingGeom.levelWidth));
+  const c14 = c14Bars(L14, model.copingRefTop, [...side.c12, ...side.c13], (x) => undersideAt(L14, x, model.endBottom, model.levelBottom, model.copingGeom.levelWidth), model.copingRebar.mainLayerGap / 1000);
   const lineCount = (line: number) => c14.filter((b) => b.line === line).length;
   const omitted = c14.filter((b) => !b.legs).length;
   rows.push({ member: 'coping', name: 'C14', size: 'H19', count: c14.length, length: c14Length(model.copingB * 1000), note: `위 2 줄 ${lineCount(1)} · ${lineCount(2)}본씩, 아래 ${[3, 4, 5, 6].map(lineCount).join(' · ')} (합 ${c14.length}) · 연직 발 생략 ${omitted}개 (하면 밖)` });