fix(rebar): side rows on the 250 grid up to the 400 mm top margin, not a fixed count of seven

C12 and C13 come from one grid from the Level underside + 127 at 250 mm, up to top − 400 mm (상면 여유). The fixed count of
seven rows is kept only for callers that give no top. P1 is unchanged (C12 5, C13 2); a taper of 3000 mm now gives C12 11
and C13 2, and the C13 first row is always the last C12 row plus 250.

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

src/core/rebar/summary.ts

@@ -190,8 +190,8 @@ export function rebarSummary(
     warnings.push({ code: 'RB-M01', message: `다주형 ${nCol}기둥: C14는 T형 기준으로 두었습니다 (기둥마다 반복 규칙 미정, Q-K11).`, target: 'coping' });
   }
   // Per row: two 일자 (side faces) and two ㄷ (one at each end), so 4 bars per row (코핑철근.md §6.2).
-  const levels = sideRowLevels(model.levelBottom, model.endBottom);
-  const side = copingSideBars(model.copingL * 1000, levels.zBottom, levels.zBreak, model.copingGeom);
+  const levels = sideRowLevels(model.levelBottom, model.endBottom, model.copingRefTop);
+  const side = copingSideBars(model.copingL * 1000, levels.zBottom, levels.zBreak, model.copingGeom, levels.zTop);
   const hook = model.copingB * 1000 - 2 * 127 + 2 * SIDE_HOOK_LEG; // ㄷ body across the width + two legs
   const c12Range = side.c12.length ? `${Math.round(side.c12[0].straight)}–${Math.round(side.c12[side.c12.length - 1].straight)}` : '—';
   // Per bar: 2 일자 (straight) and 2 ㄷ (hook body + legs), so 4 bars per row position.