Reapply "feat(rebar): B1–B4와 B5–B8 방향 교환 (B1–B4는 W 방향, B5–B8은 L 방향)"

사용자 요청으로 방향 교환을 다시 적용 (99db6a1 되돌림). 격자 키 sL/sW, 3D·단면·철근표 역할과 테스트 기대값이 교환 기준으로 돌아감.

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

src/core/rebar/summary.ts

@@ -166,16 +166,16 @@ export function linkedSpacing(name: string, model: PierModel): Pick<RebarRow, 's
   const fd = DEFAULT_FOOTING_REBAR;
   if (/^B[1-4]$/.test(name)) {
     const cycle = name === 'B2' || name === 'B4';
-    return { spacing: String(2 * fs.sAxis), actual: String(cycle ? fs.sAxis : 2 * fs.sAxis), basis: basis(fs.sAxis !== fd.sAxis) };
+    return { spacing: String(2 * fs.sL), actual: String(cycle ? fs.sL : 2 * fs.sL), basis: basis(fs.sL !== fd.sL) };
   }
   if (/^B[5-8]$/.test(name)) {
     const cycle = name === 'B6' || name === 'B8';
-    return { spacing: String(2 * fs.sPerp), actual: String(cycle ? fs.sPerp : 2 * fs.sPerp), basis: basis(fs.sPerp !== fd.sPerp) };
+    return { spacing: String(2 * fs.sW), actual: String(cycle ? fs.sW : 2 * fs.sW), basis: basis(fs.sW !== fd.sW) };
   }
-  if (name === 'B9') return { spacing: `${4 * fs.sAxis} (4s)`, actual: `${2 * fs.sAxis} (2s 엇갈림)`, basis: basis(fs.sAxis !== fd.sAxis) };
+  if (name === 'B9') return { spacing: `${4 * fs.sL} (4s)`, actual: `${2 * fs.sL} (2s 엇갈림)`, basis: basis(fs.sL !== fd.sL) };
   // B11 along L uses the 교각축 직각 grid, B12 along W uses the 교각축 grid; each is k · s (승인 2026-10-26).
-  if (name === 'B11') return { spacing: `${fs.kB11 * fs.sPerp} (${fs.kB11}s)`, actual: String(fs.kB11 * fs.sPerp), basis: basis(fs.sPerp !== fd.sPerp || fs.kB11 !== fd.kB11) };
-  if (name === 'B12') return { spacing: `${fs.kB12 * fs.sAxis} (${fs.kB12}s)`, actual: String(fs.kB12 * fs.sAxis), basis: basis(fs.sAxis !== fd.sAxis || fs.kB12 !== fd.kB12) };
+  if (name === 'B11') return { spacing: `${fs.kB11 * fs.sL} (${fs.kB11}s)`, actual: String(fs.kB11 * fs.sL), basis: basis(fs.sL !== fd.sL || fs.kB11 !== fd.kB11) };
+  if (name === 'B12') return { spacing: `${fs.kB12 * fs.sW} (${fs.kB12}s)`, actual: String(fs.kB12 * fs.sW), basis: basis(fs.sW !== fd.sW || fs.kB12 !== fd.kB12) };
   if (name === 'B10-1' || name === 'B10-2') return { spacing: String(fs.sV), actual: String(fs.sV), basis: basis(fs.sV !== fd.sV) };
   if (name === 'S1') return { spacing: String(b.spacingS1), actual: String(b.spacingS1), basis: basis(b.spacingS1 !== bd.spacingS1) };
   if (name === 'S2') return { spacing: String(b.spacingS2), actual: String(b.spacingS2), basis: basis(b.spacingS2 !== bd.spacingS2) };